This guide organizes sixty teaching concepts into ten sequenced groups, moving from collection requirements and time points through item-level coding for cognition, function, wounds, and medications. Each concept pairs a decision rule with a resolved hypothetical case and a common error, so you practice applying OASIS-E2 guidance rather than memorizing it. Work the groups in order, since later items build on conventions introduced earlier. Use it alongside the current CMS guidance manual and quarterly Q&As; the references below identify the source materials supporting each rule.
OASIS Fundamentals and Collection Requirements
1. All-Payer OASIS Collection Trigger
Since July 1, 2025, OASIS collection and submission are required when four conditions converge: any pay source, skilled services per the Medicare home health definition, no OASIS exemption, and an SOC M0090 date on or after July 1, 2025. Missing any one condition changes the decision.
Example: A self-pay patient admitted in August 2026 receives skilled wound care from a Medicare-certified agency; all four conditions are met, so the agency must collect and submit OASIS.
Mistake to avoid: Assuming only Medicare or Medicaid patients require OASIS; charity-based, no-payer, and self-pay skilled patients are all included.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
2. Patients Exempt from OASIS Collection
Three groups are exempt regardless of payer: patients under age 18, patients receiving maternity services, and patients receiving only personal care, housekeeping, or chore services. Any skilled service alongside these removes the exemption and triggers collection.
Example: A 30-year-old receiving only homemaker and chore services is exempt; once ordered skilled nursing visits begin, the exemption disappears and OASIS becomes required.
Mistake to avoid: Treating the under-18 exemption as permanent; a patient who turns 18 mid-stay begins OASIS at the next time point.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
3. Skilled Services Definition Drives the Requirement
Agencies apply the Medicare home health benefit definition of skilled services regardless of payer. If any service meets that definition, OASIS is required; if none do, it is not. Other benefit criteria like homebound status are deliberately not considered for this determination.
Example: A private-pay patient receives OT only, and the services meet the Medicare skilled definition; OASIS is required even though OT alone never establishes Medicare benefit eligibility.
Mistake to avoid: Skipping OASIS because the patient fails homebound or intermittent-care criteria; those coverage rules do not apply to this determination.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
4. Loaned Employee Agreements
When a company other than the Medicare-certified agency provides services using agency staff under a loaned employee agreement, OASIS is not required. Examples include a nurse managing PICC dressing changes under contract to a pharmacy or an assisted living program using agency staff.
Example: An agency nurse performs PICC line dressing changes under contract with a pharmacy company; no OASIS is collected because the loaned-employee arrangement applies.
Mistake to avoid: Collecting OASIS on loaned-employee visits, which fall outside the agency's own home health episode of care.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
5. Disciplines Permitted to Complete OASIS
Only an RN, PT, SLP, or OT may complete the comprehensive assessment including OASIS. LPNs/LVNs, PTAs, COTAs, medical social workers, and home health aides may never be responsible for it, though they may contribute information through collaboration under agency policy.
Example: A physical therapist assistant treating the patient reports mobility observations to the assessing PT, but the PT alone completes and signs the comprehensive assessment.
Mistake to avoid: Allowing a medical social worker to complete OASIS because social work counts as a skilled professional service.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
6. RN Role When Nursing Is Ordered at Referral
When both nursing and therapy are ordered on the initial referral, the RN must perform the initial assessment visit and SOC comprehensive assessment. If nursing is declined or unneeded, that visit does not establish SOC, and the assessment cannot precede the SOC date.
Example: The RN assesses Monday, but PT's billable Tuesday visit establishes SOC; the RN returns by Sunday to complete the OASIS within five days.
Mistake to avoid: Signing a comprehensive assessment dated before the SOC date, which fails the Conditions of Participation.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
Time Points and Reasons for Assessment
7. SOC Assessment Timeframe
The SOC comprehensive assessment including OASIS must be completed on or within five calendar days after the SOC date, counting the SOC date as day zero. The SOC date itself is the date of the first reimbursable service, not necessarily the assessment visit.
Example: With SOC established on Tuesday, the comprehensive assessment may be completed any day through Sunday; completing it Monday falls outside the five-day window.
Mistake to avoid: Counting the SOC date as day one, which silently shortens the allowable assessment window by one day.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
8. ROC Timeframe and Physician-Ordered ROC Date
The ROC assessment must be completed within two calendar days of the facility discharge date, the agency's knowledge of the patient's return, or a physician-ordered ROC date. When a physician specifies a resume date, that date becomes M0032 and the assessment deadline runs from it.
Example: Discharged Friday with a physician order to resume Monday: M0032 is Monday, and M0090 may be completed Monday, Tuesday, or Wednesday.
Mistake to avoid: Running the two-day clock from hospital discharge when a later physician-ordered resumption date controls the deadline.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
9. Recertification Window and Missed Recertifications
Recertification assessments are completed during days 56 through 60 of each 60-day certification period, counted from the original SOC date, not from any ROC. If the window is missed, the agency completes the assessment late rather than discharging and readmitting the patient.
Example: A recertification missed on day 60 is completed on day 63; M0090 reports the actual completion date with documentation explaining the delay.
Mistake to avoid: Discharging and readmitting the patient to escape a missed recertification window; guidance directs a late completion instead.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
10. ROC Serving Dual Resumption and Recertification Functions
When a patient returns from an inpatient stay during days 56 through 60, a single ROC assessment may serve both resumption and recertification functions. This works when discharge occurs on day 54 or 55 and the ROC is completed on day 56 or 57 respectively.
Example: Discharged home on day 54 with no physician-ordered ROC date, the agency completes the ROC on day 56, satisfying resumption and recertification in one assessment.
Mistake to avoid: Completing a separate recertification when a timely ROC during days 56 through 60 already serves both functions.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
11. Transfer RFAs and Qualifying Inpatient Stays
RFA 6 applies when the agency keeps the patient; RFA 7 when the patient is discharged to the facility. Both require an inpatient stay of 24 hours or longer for reasons other than diagnostic testing; ER time and observation holds never qualify regardless of duration.
Example: A 30-hour observation hold never qualifies, so no Transfer OASIS is completed; a 24-hour acute admission for treatment triggers RFA 6 or 7.
Mistake to avoid: Coding a transfer because the patient spent a long afternoon in the emergency department.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
12. Death at Home and Single-Visit Episodes
RFA 8 covers deaths at home, in the ED, during outpatient surgery, in transport before ED arrival, or under 24 hours after admission; deaths after a qualifying inpatient stay are reported as transfers instead. Discharge OASIS is not collected when only one visit was made.
Example: A patient who dies in the emergency department is coded RFA 8; a patient discharged after a single home visit receives no discharge OASIS.
Mistake to avoid: Submitting a discharge OASIS for a single-visit quality episode when neither Medicare PPS nor another payer requires it.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
Conventions, Accuracy, and Corrections
13. Day of Assessment Definition
Unless an item specifies otherwise, coding reflects patient status on the day of assessment: the 24 hours immediately preceding the home visit plus the time the clinician spends in the home. This standard window captures fluctuations regardless of visit time.
Example: A patient who transfers safely each morning but is unsteady by evening is coded from overall performance across the full 24-hour window.
Mistake to avoid: Coding only from the minutes directly observed during the visit, ignoring the preceding 24 hours.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
14. Greater-Than-50-Percent Rule
When ability or status varies during the time period under consideration, report what is true more than 50 percent of the time unless the item specifies differently. For multi-task items, weight more frequently performed tasks more heavily when abilities differ across tasks.
Example: A patient manages buttons independently most mornings but needs help roughly a third of the time; code the performance that dominates the period.
Mistake to avoid: Defaulting to the more dependent code whenever performance varies even slightly during the look-back period.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
15. Dash Responses and Unplanned Discharges
A dash means no information is available and CMS expects its use to be rare. After an unplanned discharge with no in-home visit, the last clinician to see the patient completes items from that visit plus documentation from the last five visit days; interview items like BIMS allow only a dash.
Example: A patient abruptly relocates out of state; with no BIMS interview documented in the last five visit days, C0500 receives a dash.
Mistake to avoid: Using dashes routinely for difficult or time-consuming items rather than for genuinely missing information.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
16. Collaboration and M0090
The assessing clinician may collaborate with staff, caregivers, and physicians, but remains responsible for every response. M0090 records the last date information used to determine OASIS coding was gathered and documented, which may follow a phone call and need not match a visit date.
Example: The clinician confirms a medication question with the pharmacist on Wednesday; M0090 becomes Wednesday even though the home visit occurred Tuesday.
Mistake to avoid: Automatically entering the visit date as M0090 when later-gathered information changed an item's coding.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
17. Modification Versus Inactivation Records
Corrections to records already accepted in iQIES use a modification for clinical errors or non-key field errors. An inactivation is required when the event never occurred or any key field is erroneous, because users cannot change key fields; a replacement record follows.
Example: A clinical error in a non-key field is corrected by modification; a record submitted for a transfer that never happened must be inactivated and replaced.
Mistake to avoid: Attempting to modify key field errors instead of inactivating the record and submitting a replacement.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
18. Agency Audit Approaches
Clinical record audits compare OASIS responses with other documentation, reviewing at least five SOC and five discharge records monthly. Clinical audit visits pair a supervisor or peer with the assessing clinician on three to four quarterly visits, comparing codes without discussing items during the visit.
Example: SOC OASIS shows independent ambulation while subsequent visit notes describe standby assistance; the discrepancy is reviewed with the assessing clinician for explanation or correction.
Mistake to avoid: Treating audit approaches as CMS mandates; they are recommended practices with agency-set frequency and staffing.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
Administrative and Tracking Items
19. M0030 Start of Care Date
M0030 records the date of the first reimbursable service, which stays fixed until discharge. It does not change with a new certification period, an added service, or a later discipline; non-billable assessment visits by an RN or therapist never establish the SOC date.
Example: PT's billable Tuesday visit establishes SOC even though the RN assessment occurred Monday as a non-billable visit; M0030 remains Tuesday for the episode.
Mistake to avoid: Updating M0030 when a new discipline or service begins weeks into an established episode.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
20. M0102 Physician-Ordered SOC or ROC Date
M0102 captures a specific single date ordered by the physician or allowed practitioner to start or resume care; a range of dates does not qualify. A revised order must arrive on or before the original ordered date, otherwise code NA and report the original referral date in M0104.
Example: Orders state care should start sometime next week; no single date exists, so M0102 is NA and the initial visit must occur within 48 hours of referral.
Mistake to avoid: Entering an approximate or preferred date when the order provides no specific single date.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
21. M0104 Date of Referral
M0104 is the most recent date the agency received adequate authorization to begin care, confirmed by a physician who will provide the plan of care. Payer authorization dates, such as a Medicare Advantage case manager approval, are not referral dates.
Example: A hospitalist refers but will not follow the patient; the date the attending physician agrees to oversee the plan of care becomes M0104.
Mistake to avoid: Recording the Medicare Advantage authorization date instead of the date physician-confirmed referral information was received.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
22. M0150 Current Payment Sources
M0150 lists every payer the agency will bill, not just the primary; pending sources are excluded and uncertain sources omitted. Code 2 covers Medicare Advantage and Part C, code 3 Medicaid waiver programs, and combined Medicare-Medicaid managed plans check both applicable responses.
Example: A patient with Medicare FFS billing plus waiver-funded personal care codes both the Medicare response and code 3 for the billed waiver services.
Mistake to avoid: Marking only the primary payer when the agency will bill multiple sources during the episode.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
23. M1000 and M1005 Inpatient Facility Look-Back
These items capture discharges from inpatient facilities in the 14 days before SOC or ROC, counting the SOC date as day zero and including a discharge on day zero. Code 2 for a skilled nursing facility requires Medicare Part A skilled care; otherwise code 1 applies.
Example: A SNF discharge eight days before SOC without Part A skilled care codes 1, long-term nursing facility, rather than response 2.
Mistake to avoid: Coding every nursing facility discharge as response 2 without verifying Part A skilled care was received.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
24. A1255 Transportation Barrier
A1255 asks whether lack of reliable transportation in the past 12 months kept the patient from medical appointments, meetings, work, or daily needs. A patient who declines to respond is coded 7 with no proxy or record use; an unable patient permits proxy, then records.
Example: A confused patient's record shows the spouse drove them to all appointments; with no proxy available, the documentation supports coding 1, No.
Mistake to avoid: Overriding a patient's refusal by coding from family report or medical record documentation.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
Sensory, Cognitive, and Mood Assessment
25. B0200 Hearing Assessment With Appliances
Hearing is assessed with the patient's usual appliance in place and operational, including amplifiers or microphone-headphone alternatives. Levels run from adequate through minimal difficulty in noisy settings, moderate difficulty requiring speaker adjustments, to highly impaired with no useful comprehension.
Example: A patient hears one-on-one conversation clearly but misses discussion across a noisy dinner table; after moving to a quiet room hearing is adequate, so code 1.
Mistake to avoid: Coding impaired hearing while the patient's hearing aid sits uncharged in a drawer at home.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
26. B1000 Vision Testing Alternatives
Vision is tested with customary glasses or magnifier and adequate lighting, reading from headlines down to fine print. Patients who cannot read may be shown numbers or pictures in regular and large sizes; those unable to follow directions are observed for eye tracking.
Example: An illiterate patient correctly names small pictures displayed in two sizes, supporting code 0, adequate vision, despite never having learned to read words.
Mistake to avoid: Coding impaired vision because the patient cannot read, when the deficit is literacy rather than sight.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
27. B1300 Health Literacy Self-Report Only
B1300 asks how often the patient needs help reading instructions or written material from doctors or pharmacies. It is strictly a patient self-report item; no proxy, caregiver report, or chart documentation may substitute, even when family observations contradict the patient.
Example: The patient answers never, even though the son describes repeatedly explaining written discharge instructions; the self-report controls and code 0 stands.
Mistake to avoid: Letting an insistent caregiver's observations override the patient's own answer on this self-report item.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
28. C0200 BIMS Repetition Scoring
C0200 scores only the number of words repeated correctly on the first attempt; second and third attempts, with category cues, support learning but never change the score. Words may be recalled in any order or embedded in a sentence and still count.
Example: The patient first repeats two of three words, then repeats all three after category cues; C0200 remains 2 because only the first attempt is scored.
Mistake to avoid: Crediting an improved second or third repetition, which inflates the summary score improperly.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
29. C0500 BIMS Summary and Stop Rules
C0500 sums C0200 through C0400C. Code 99 when the patient refuses or gives nonsensical answers to four or more items, or when some but not all items are dashed; stop after C0300C if every response so far is nonsensical or absent, dashing C0400.
Example: Every response through day-of-week is a refusal; stop the interview, dash C0400A through C, and enter 99 as the C0500 summary.
Mistake to avoid: Treating a total score of zero as incomplete; zeros from genuinely wrong answers allow the interview to continue.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
30. D0150 and D0160 PHQ Scoring Rules
The PHQ-2 ends after D0150A and B when both frequency responses are 0 or 1, summing only those two items in D0160. Otherwise all nine items are asked; with one or two missing frequency values, multiply the remaining sum by 9/8 or 9/7, and code 99 for three or more missing.
Example: Eight answered frequency items sum to 11; multiplying by 1.125 gives 12.375, which rounds to 12 and is entered in D0160.
Mistake to avoid: Summing only the answered items without applying the required prorating multiplier for missing values.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
Delirium, Behavior, and Support System
31. C1310A Acute Mental Status Change
C1310A compares current mental status with the patient's baseline, using family report, records, and observation. Code 1 only for an alteration representing an acute change from baseline; longstanding confusion without new worsening is not an acute change.
Example: A long-demented patient suddenly becomes agitated and disoriented to person; the new behaviors represent an acute change and code 1 against their prior baseline.
Mistake to avoid: Coding chronic, stable confusion as an acute change simply because confusion is present at assessment.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
32. C1310B-D Fluctuation When Sources Disagree
For inattention, disorganized thinking, and altered consciousness, code 2 when the behavior varies during assessment or when information sources disagree about its presence. Code 1 requires all sources to agree the behavior is constantly present; any single source reporting the symptom prevents code 0.
Example: The patient tracked questions early in the interview but attention wandered later; variation within the visit itself codes 2, behavior present and fluctuating.
Mistake to avoid: Averaging disagreeing sources into behavior-not-present instead of applying the fluctuation response.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
33. D0700 Social Isolation Self-Report
D0700 asks how often the patient feels lonely or isolated from those around them. Like health literacy, it is a patient self-report item with no other permitted source; code 7 for declines and 8 when the patient is unable to respond.
Example: A remote-dwelling patient with daily visiting neighbors reports never feeling lonely; code 0 reflects the self-report, not the rural address or living arrangement.
Mistake to avoid: Inferring isolation from living alone or rural residence instead of asking the patient directly.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
34. M1100 Living Situation and Caregiver Availability
M1100 pairs living arrangement with availability of in-person assistance from non-agency caregivers. A temporarily staying caregiver still means living alone; telephone availability never counts; an assisted living apartment is a congregate situation regardless of living alone within it.
Example: Daughters rotate staying since hospital discharge; the patient remains in the lives-alone row with around-the-clock assistance because the arrangement is temporary.
Mistake to avoid: Counting relatives available only by telephone as providing in-person assistance for this item.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
35. M2102 Caregiver Assistance Categories
M2102 rates non-agency caregivers' ability and willingness across ADLs, medication administration, medical procedures, and supervision for cognition. When responses differ, select the one representing the caregiver's greatest barrier; devices with medical impact count under procedures, not ADL assistance.
Example: A caregiver helps with dressing but needs training to perform wound care; report the training-and-support level because it represents the greatest barrier.
Mistake to avoid: Rating only the easiest category the caregiver manages rather than the response showing the greatest barrier.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
36. M1745 Disruptive Behavior Frequency
M1745 codes how often any disruptive or dangerous behaviors occur, including but not limited to wandering, agitation, combativeness, and sun-downing, identified by diagnosis or clinician judgment. Consider all such behaviors, not merely those listed in M1740, then rate frequency.
Example: A patient yells at caregivers every evening, a behavior absent from M1740's list; it still counts toward M1745's frequency rating.
Mistake to avoid: Restricting M1745 to behaviors checked in M1740 rather than considering all disruptive or dangerous behaviors.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
Functional Status: M-Items and Section GG
37. M1800 Grooming Multi-Task Rule
Grooming excludes bathing, hair shampooing, and toileting hygiene. When ability differs across grooming tasks, code the level describing the majority of tasks, weighting more frequently performed activities like washing hands and face above occasional ones like fingernail care.
Example: A patient washes face and hands independently every day but cannot trim fingernails; the frequently performed tasks dominate, supporting the more independent grooming code.
Mistake to avoid: Letting an occasional task like nail trimming pull the code down to full assistance.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
38. M1830 Bathing Responses 4, 5, and 6
Code 4 requires independent, safe bathing outside the tub or shower, including sink or basin bathing. Code 5 covers patients unable to use the tub or shower who need intermittent or continuous assistance; code 6 applies when another person performs all bathing anywhere.
Example: The home has no functioning shower, and the patient bathes independently and safely at the sink with a basin; code 4 applies rather than 5.
Mistake to avoid: Automatically coding 5 whenever the home lacks a usable tub or shower, ignoring independent sink bathing.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
39. M1850 Transferring Assistance Combinations
Code 1 applies with either minimal human assistance or a device alone, never both. Code 2 covers patients needing both a device and minimal help, or who bear weight and pivot but need more than minimal assistance; code 3 fits inability to bear weight or pivot when not bedfast.
Example: A patient transfers using a sliding board while a helper steadies less than a quarter of the effort; both device and human help are needed, so code 2.
Mistake to avoid: Coding 1 when a device and human assistance are both required for the transfer to be safe.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
40. GG0100 Prior Functioning
GG0100 reports usual ability before the current illness, exacerbation, or injury, whichever most recently initiated this episode. Code 3 for full independence with devices, 2 when any activity needed partial help including unavailable caregivers or camera-based supervision, and 8 when unknown.
Example: Before admission the patient negotiated stairs only by stair lift, without any helper; GG0100C codes 3, independent, because any safe means counts.
Mistake to avoid: Downgrading prior independence because the patient relied on equipment such as a stair lift.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
41. GG0130 and GG0170 Performance Codes
Section GG performance codes are effort-based: 06 independent, 05 setup or clean-up before or after, 04 supervision or touching, 03 when the helper gives less than half the effort, 02 more than half, and 01 for all helper effort or two helpers. Devices alone never worsen the code.
Example: A patient walks 50 feet with a rolling walker and no helper at all; code 06 applies because a device alone never adds a helper level.
Mistake to avoid: Assigning a supervision code merely because an assistive device is in use during the activity.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
42. GG Activity Not Attempted Codes
Use 07 for refusal, 09 when the patient did not perform the activity before the current illness, 10 for environmental limitations like missing equipment, and 88 when a medical condition or safety concern prevented an activity previously performed. Exhaust report, collaboration, and similar-activity assessment first.
Example: After a stroke the patient walks only 30 feet even with assistance; GG0170J codes 88 because 50 feet was achievable before the current illness.
Mistake to avoid: Jumping to an activity-not-attempted code before exhausting patient report, collaboration, and similar-activity assessment.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
Elimination, Diagnoses, and Health Conditions
43. M1610 Incontinence, Catheter, and Diversion
Code 0 applies to anuria, pouched urinary diversions, and ostomies for urinary drainage. Code 1 covers any incontinence, including occasional leaks, plus timed-voiding dependence; code 2 applies to any catheter use for drainage, including intermittent, and when both incontinence and catheter exist.
Example: A patient with an ileal conduit codes 0; a separate patient whose catheter drainage bag leaks at the connection stays in the catheter pathway, not incontinence.
Mistake to avoid: Coding a leaking urinary drainage appliance as incontinence when the problem is equipment, not the patient.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
44. M1021 and M1023 Diagnosis Roles
M1021 is the chief reason for home care, most related to the current plan; M1023 lists comorbidities actively addressed or potentially affecting treatment response. Sequence other diagnoses by impact on care needs, not symptom control ratings, and exclude resolved conditions like post-cholecystectomy cholecystitis.
Example: Difficult-to-control diabetes is listed above a poorly controlled toenail fungus because diabetes drives the patient's care needs more heavily.
Mistake to avoid: Ordering M1023 entries by symptom control ratings rather than by each diagnosis's impact on care.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror); CDC ICD-10-CM Official Guidelines, FY 2027
45. M1028 Active Diagnoses Documentation Standard
M1028 responses for PVD, PAD, and diabetes require a physician or authorized practitioner documented diagnosis present at assessment. A patient-reported history without documentation codes 3, none of the above; a documented complication like neuropathy alone does not establish diabetes.
Example: The patient reports 20 years of diabetes, but no provider documentation exists anywhere in the record; code 3, none of the above, despite the self-report.
Mistake to avoid: Inferring diabetes from a documented complication like neuropathy without any documented diabetes diagnosis.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
46. J1800 and J1900 Falls and Intercepted Falls
Falls include witnessed, unwitnessed, and intercepted events where the patient would have fallen without self-catch or interception, occurring anywhere during the episode except qualifying inpatient stays. Anticipated losses of balance during intentional balance training do not count unless major injury results.
Example: During gait training the therapist bears part of the patient's weight after an unexpected stumble; the interception counts as a fall and J1800 codes 1.
Mistake to avoid: Excluding unwitnessed falls, or falls occurring away from home, from the episode's fall count.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
47. J1900 Injury Classification
Each fall is coded once at its highest injury level: no injury, injury except major including skin tears, bruises, and sprains, or major injury including fractures, dislocations, and head injuries. Pathological fractures from bone disease, not the fall, are not major fall injuries.
Example: A fall produces a hip fracture the physician attributes to osteoporosis rather than the fall; J1900C stays 0 because the fracture is pathological.
Mistake to avoid: Counting multiple injuries from one fall as separate falls instead of one entry at the highest level.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
48. M1400 Dyspnea and Oxygen Use
Dyspnea coding reflects actual home oxygen use, not the physician's order. Continuous users are assessed while using oxygen; intermittent users are assessed without it. Chairfast or bedbound patients are evaluated by the exertion their ADLs or rest state demands.
Example: An intermittent oxygen user becomes breathless while dressing without oxygen; code the response observed off oxygen, regardless of the ordered regimen.
Mistake to avoid: Basing the dyspnea code on the physician's oxygen order rather than the patient's actual home use.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
Skin and Wound Assessment
49. M1306 Unhealed Stage 2 or Higher Trigger
M1306 is coded 1 when any unhealed Stage 2, 3, or 4 pressure ulcer or any unstageable pressure ulcer exists. Stage 1 injuries and healed ulcers of any prior stage alone code 0; Stage 1 and deep tissue injury with intact skin are never considered healed.
Example: A patient has one Stage 1 injury and a fully healed Stage 3; M1306 codes 0 because no unhealed stageable ulcer at Stage 2 or higher remains.
Mistake to avoid: Counting a Stage 1 injury or a healed ulcer of any prior stage toward a code 1.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
50. No Reverse Staging Principle
A pressure ulcer previously classified at a higher numerical stage keeps that stage until healed or it becomes unstageable, even while granulating and shrinking. Lost muscle, fat, and dermis are never restored, so a healing Stage 4 remains Stage 4 documentation.
Example: A Stage 4 sacral ulcer is now shallow and fully granulating; it is still reported as Stage 4 at every assessment until it closes.
Mistake to avoid: Down-staging a healing Stage 4 ulcer to a lower stage in order to document improvement.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
51. Unstageable Ulcers and Visible Stage 4 Structures
Ulcers covered completely by slough or eschar so depth cannot be visualized are unstageable. But if any bone, tendon, muscle, or joint capsule is visible, code Stage 4 regardless of necrotic tissue present; known ulcers under non-removable devices are unstageable in a separate category.
Example: Eschar rings the wound edge yet tendon is visible at the base; the visible Stage 4 structure controls, so the ulcer is coded Stage 4.
Mistake to avoid: Coding unstageable whenever slough or eschar appears, even when Stage 4 structures remain visible.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
52. M1307 Oldest Stage 2 at Discharge
M1307 identifies whether the oldest unhealed Stage 2 at discharge was present at the most recent SOC or developed since, with a date when new. A Stage 1 that progressed to Stage 2 during the episode codes 2, developed since SOC, using the Stage 2 identification date.
Example: No ulcer existed at SOC, a Stage 1 appeared on day 10, and an open Stage 2 emerged by day 20; code 2 with the day 20 date.
Mistake to avoid: Reporting the Stage 1 appearance date instead of the date the ulcer first met Stage 2 criteria.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
53. Stasis Ulcer Observable Status
M1330 distinguishes observable stasis ulcers, unobservable ones hidden under non-removable dressings like Unna boots, and both. Arterial ulcers never count here. Once a stasis ulcer fully epithelializes it is healed and drops from reporting; M1334 then grades the most problematic observable ulcer's healing status.
Example: The patient has one visible ankle ulcer and one hidden under a non-removable Unna boot; code 1, yes, both observable and unobservable ulcers.
Mistake to avoid: Including arterial lesions or fully epithelialized, healed ulcers in the stasis ulcer responses.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
54. M1340 Surgical Wound Boundaries
Surgical wounds include incision lines, orthopedic pin sites, central line sites, drained wounds, and implanted infusion devices; a primarily closed site generally stops being reportable around 30 days of epithelialization. Bowel ostomies, mucosal and vaginal-approach procedures, and peripherally inserted PICC lines are excluded.
Example: A pressure ulcer surgically closed with a flap becomes a surgical wound until healed and is no longer counted in M1311.
Mistake to avoid: Reporting a PICC line site or a bowel ostomy as a surgical wound on this item.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
Medications, Treatments, and Care Transitions
55. N0415 High-Risk Drug Class Indication
For each listed high-risk class the patient takes, Column 2 is checked only when a patient-specific indication is documented for every medication in that class. Code by pharmacologic classification regardless of use; antiplatelets and port-flush anticoagulants are excluded from the anticoagulant class.
Example: A patient takes two opioids, one with a documented indication and one without; Column 2 remains unchecked because all medications in the class need indications.
Mistake to avoid: Checking the indication column when any single drug in the class is documented rather than all.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
56. M2001 and M2003 Medication Issue Follow-Up
A clinically significant medication issue is one warranting physician communication and completed actions by midnight of the next calendar day. M2003 codes 1 only when two-way communication and all feasible actions met that deadline; a physician's late reply alone forces code 0.
Example: Duplicate antihypertensives are identified Monday morning; the prescriber confirms the discontinuation order Tuesday evening, within the deadline, so M2003 codes 1.
Mistake to avoid: Coding 1 when the physician's return call or the completed action arrives after midnight of the next day.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
57. M2020 Oral Medication Management Levels
M2020 assesses ability, not willingness, for all oral medications on the plan of care. Code 1 when another person pre-fills planners or modifies containers; code 2 for needed reminders; code 3 when the patient cannot take the right dose at the right time even with supports.
Example: A patient takes correctly dosed medications only when her daughter telephones at the scheduled times; code 2, able with reminders from another person.
Mistake to avoid: Counting a device reminder the patient independently sets and manages as requiring another person.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
58. K0520 Nutritional Approach Distinctions
At SOC and ROC, check approaches on the current care plan even if unused at assessment. Mechanically altered diets change texture and are not automatically therapeutic; therapeutic diets are defined by why they are required, such as fluid restrictions prescribed to manage disease.
Example: Honey-thick liquids ordered for dysphagia check mechanically altered diet; a prescribed fluid restriction for heart failure also checks therapeutic diet because of why it is required.
Mistake to avoid: Treating every texture-modified diet as a therapeutic diet rather than asking why the diet is required.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
59. O0110 Special Treatments Selection
O0110 captures treatments on the current plan, in any setting, including self-performed ones. IV medications exclude line-maintenance flushes; anticoagulation excludes subcutaneous routes; IV access is coded only when a line is currently in place, even if a port exists unused.
Example: A patient with an idle port receives oral chemotherapy; check central IV access and oral chemotherapy, but not IV medications, since nothing is infusing.
Mistake to avoid: Coding IV access for a planned line or a catheter that is not currently in place.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
60. A2120 Through A2124 Medication List Transmission
At transfer or discharge to a subsequent provider, code whether the reconciled medication list was provided and by which routes: shared EHR, health information exchange, verbal, paper including fax, or other. A shared EHR counts even without confirmed access; an unaware agency at transfer codes A2120 as NA.
Example: The receiving hospital reads the medication list through a shared EHR; A2120 codes 1 and A2122 codes EHR, without requiring confirmation the hospital opened it.
Mistake to avoid: Requiring proof the recipient actually accessed the record before coding electronic transmission routes.
Reference: CMS OASIS-E2 Guidance Manual (OASIS Answers mirror)
References and further reading
Source links checked on Oct 2, 2026.