The start of care date (OASIS item M0030) is the date a home health agency delivers the first reimbursable service to a patient. Every other date in the admission counts from it: the 5-day window to complete the comprehensive assessment, the Notice of Admission deadline, the 60-day certification period, and the recertification window on days 56 to 60.
It sounds too simple to get wrong. It gets wrong constantly, because four dates travel together on the OASIS and three of them look like a start of care date if you squint. This page defines each one, says which clock it starts, and walks the three mix-ups I see most.
| Item | What it is | Which clock it starts |
|---|---|---|
| M0104 Date of Referral | The day the agency received a valid referral | The 48-hour initial assessment visit clock |
| M0102 Physician-ordered Start of Care Date | A specific date the practitioner ordered care to begin, if there was one | Replaces the 48-hour clock: the visit is due on that date |
| M0030 Start of Care Date | The first visit where a reimbursable service is delivered | The 5-day assessment window, the Notice of Admission, and the 60-day certification period |
| M0090 Date Assessment Completed | The last day the clinician gathered information and finished documenting the assessment | The 30-day transmission deadline |
M0030: The Start of Care Date
The OASIS-E2 Guidance Manual defines it in one sentence: the start of care date "is the date that the first reimbursable service is delivered." The surveyor guidance says the same thing in clinical terms:
"The start of care date is the first visit where the HHA provides hands on, direct care services or treatments to the patient. If an initial assessment is completed without any direct care services being provided by the HHA during the assessment visit, the date of that initial assessment visit would not be the start of care date." (State Operations Manual, Appendix B, tag G520)
Three properties follow, all from the manual's M0030 guidance:
- There is one per admission. "The Start of Care date does not change with a new certification period, or when a new service is added during the episode. There is only one Start of Care date for the episode."
- It is the billing date too. "It should correspond to the start of care date used for other documentation, including billing or physician orders." If the OASIS says March 3 and the claim says March 4, one of them is wrong.
- In a multi-discipline case, it is the first billable visit, whichever discipline makes it. "In multidiscipline cases, coverage criteria, regulatory requirements (such as the Conditions of Participation), and agency policy establish which discipline's visit is considered the start of care. A reimbursable service must be delivered to be considered the start of care."
The therapy-only case with a nursing assessment is the one that trips people. Some agencies send a registered nurse to do the start of care assessment even when only therapy is ordered. That nursing visit is not billable, so it is not the start of care. The manual's instruction: "When the agency's policy/practice is for an RN to perform the SOC assessment in a therapy-only case and the therapist's first visit is the start of care date (i.e., the first billable visit), the non-billable nursing assessment visit must be made the same day or within five days after the therapist's first visit." The therapist's visit is day 0. The nurse has to assess within the same 5-day window.
Warning
The manual's own words: "Accuracy of this date is essential; many other aspects of data collection are based on this date." A start of care date that is one day off moves the certification period, the recertification window, the Notice of Admission deadline and the OASIS completion deadline by one day each. Fix it at intake, not at recert.
M0104: The Date of Referral
This is the date that starts the 48-hour clock for the initial assessment visit, so it matters what counts. The manual:
"A valid referral is considered received when the agency has received adequate information about a patient (such as name, address/contact info, and diagnosis and/or general home care needs) to initiate patient assessment and confirmed that the referring physician/allowed practitioner or another physician/allowed practitioner, will provide the plan of care and ongoing orders."
Two conditions, both required. Information about the patient, and a practitioner who will own the plan of care. A referral from a hospitalist who will not follow the patient is incomplete until an attending agrees to: "The agency will note the date the alternate or attending physician/allowed practitioner agreed to follow the patient as the referral date (M0104)."
What is not a referral:
- Payer authorization. "The date authorization was received from the patient's payer is NOT the date of the referral (for example, the date the Medicare Advantage case manager authorized service is not considered a referral date)."
- A heads-up. Calls from assisted living staff or family "who contact the agency to prepare the agency for possible admission" do not count.
And the referral date can move. If the start of care is delayed by the patient's condition or the practitioner's request, say an extended hospitalization, "the date the agency received the updated/revised referral for home care services would be considered the date of referral." You enter the most recent one.
Tip
Practice, not rule: log the referral date and the time you got it, and log what was still missing. "Referral 3/1 10:40, attending confirmed 3/1 15:10" is a chart that explains itself when a surveyor asks why the first visit was March 3.
M0102: The Physician-Ordered Start of Care Date
When the practitioner names a specific date for care to begin, the initial assessment visit is due on that date instead of within 48 hours of the referral. The regulation lists it as the third option: the visit must be held "either within 48 hours of referral, or within 48 hours of the patient's return home, or on the physician or allowed practitioner-ordered start of care date" (42 CFR 484.55(a)(1)).
The manual's rules for what qualifies:
- It has to be a single date. "The physician/allowed practitioner must give a specific date to initiate or resume care, not a range of dates." If no single date is given, the 48-hour clock applies.
- It applies regardless of service type. The item intent covers an order to "provide the first covered service ... regardless of the type of services ordered (for example, therapy only)."
- A revised date must arrive before the old one passes. "A revised physician's ordered SOC/ROC date must be received on or before the date of the previous physician's ordered SOC/ROC." If the extension comes in after the ordered date has gone by, you "report NA for M0102 and report the original referral date in M0104."
- Orders from allowed practitioners count. A physician assistant, nurse practitioner or other advanced practice nurse satisfies the physician's-order condition.
The manual's example is worth keeping: a patient discharged home on May 15, with an order for home care to begin May 20 for a specified service such as physical therapy or a subcutaneous drug, has a physician-ordered start of care date of May 20. The visit is due May 20, and the start of care date (M0030) will be the day the first billable service is actually delivered, which is normally May 20 as well.
One caution from the 48-hour rule article that belongs here too: an ordered date is the practitioner's clinical decision for the patient. It is not a tool for an agency that cannot staff a weekend.
M0090: The Date Assessment Completed
M0090 is the date most often filled in wrong, because people treat it as the visit date. The manual:
"The M0090 - Date Assessment Completed is the last date that information used to complete the comprehensive assessment and determine OASIS coding was gathered by the assessing clinician and documentation of the specific information/responses was completed."
Which means:
- It is not necessarily a visit date. "In a situation where the assessing clinician needs to follow-up with the patient's family or physician to complete an OASIS item that the patient is unable to answer, M0090 should reflect that date even if no visit is provided on that date."
- It can move forward inside the window. If the clinician gathers new information during the assessment timeframe that changes the coding of an item, M0090 changes to the date that information was gathered and documented.
- It does not move for corrections. "If an error is identified at any time, it should be corrected following the agency's correction policy and M0090 would not necessarily be changed."
- It cannot be before the start of care. "Date Assessment Completed cannot be before the SOC date."
M0090 is also the anchor for the transmission deadline. The OASIS must be transmitted "within 30 days of completing the assessment of the patient" (42 CFR 484.45(a)). Thirty days from M0090, not from the start of care.
For a transfer or death at home, M0090 is "the date the agency completed the data collection after learning of the event."
The Clocks, Side by Side
| Clock | Starts at | Deadline | Source |
|---|---|---|---|
| Initial assessment visit | Referral (M0104), or return home, or the ordered date (M0102) | Within 48 hours, or on the ordered date | 42 CFR 484.55(a)(1) |
| Comprehensive assessment completion | Start of care (M0030), day 0 | Within 5 calendar days | 42 CFR 484.55(b)(1); Guidance Manual Table 1.2 |
| Notice of Admission | Start of care | Within 5 calendar days | 42 CFR 484.205(j) |
| First certification period | Start of care, day 1 | 60 days | 42 CFR 484.55(d)(1) |
| Recertification assessment | Start of care | Days 56 to 60 of each period | Guidance Manual, RFA 4 |
| OASIS transmission | Date assessment completed (M0090) | Within 30 days | 42 CFR 484.45(a) |
The referral to first visit guide walks the intake side of these. The 60-day certification tracking article covers the period arithmetic.
The Three Mix-Ups
Using the initial assessment visit date as the start of care. If a nurse does the assessment on Monday and provides no billable service, and the therapist delivers the first treatment Tuesday, the start of care is Tuesday. Monday's date on M0030 shifts every downstream deadline a day early and puts the OASIS and the claim out of agreement.
Putting the visit date in M0090. The clinician visits Tuesday, phones the daughter Thursday to finish the medication list, and signs Thursday. M0090 is Thursday. Writing Tuesday understates the assessment window you actually used and misdates the 30-day transmission clock.
Treating the authorization date as the referral date. The referral arrives Monday, the Medicare Advantage plan authorizes Wednesday. The 48-hour clock started Monday. An agency that waits for authorization before counting has already used the window.
One start of care date, every deadline computed from it
Logicly sets the certification period, the recertification window and the assessment deadlines from the start of care date the moment it is recorded, and moves the initial-visit clock when a physician orders a later start.
En español: las cuatro fechas del OASIS
Para los equipos que documentan en español, las definiciones breves. Los códigos son los mismos.
- M0030, fecha de inicio de la atención (start of care): la fecha en que la agencia presta el primer servicio reembolsable. Hay una sola por admisión y no cambia con la recertificación.
- M0032, fecha de reanudación de la atención (resumption of care): la fecha de la primera visita después de una estancia hospitalaria de 24 horas o más.
- M0090, fecha en que se completó la evaluación: el último día en que el clínico reunió información para la evaluación integral y terminó de documentarla. No tiene que coincidir con una visita. Nunca puede ser anterior a la fecha de inicio.
- M0102, fecha de inicio ordenada por el médico: una fecha específica, no un rango, en la que el médico ordenó que comenzara la atención. Si existe, la visita inicial se hace ese día.
- M0104, fecha de la referencia: el día en que la agencia recibió una referencia válida, con datos suficientes del paciente y un médico que seguirá el plan de atención. La autorización del pagador no es la referencia.
Para los distintos tipos de OASIS, la fecha de M0090 es siempre la misma regla: el último día en que se reunió y documentó la información de esa evaluación, sea de inicio, reanudación, recertificación, transferencia o alta.
Key Takeaways
- The start of care date is the first visit with a reimbursable service. Not the referral date, not the assessment date, not the ordered date unless care actually began then.
- There is one start of care date per admission. Recertification and resumption of care do not move it.
- The referral date needs patient information and a practitioner who will own the plan of care. Payer authorization is not a referral.
- An ordered start date must be a single date, and a revised one must arrive before the first one passes.
- The date assessment completed is the last day information was gathered and documented. It can be a phone-call day, and it starts the 30-day transmission clock.
Frequently asked questions
What is the start of care date in home health?
The start of care date (OASIS item M0030) is the date the agency delivers the first reimbursable service to the patient. CMS surveyor guidance puts it as the first visit where the agency provides hands-on, direct care. It is set once per admission and does not change at recertification or when a new discipline is added.
Is the start of care date the same as the date of the initial assessment visit?
Not always. If the initial assessment visit includes a billable skilled service, that visit is the start of care. If the assessment is done without any direct care being provided, CMS says the date of that visit is not the start of care date. The start of care is the first visit where hands-on care is delivered.
What is M0090, the date assessment completed?
M0090 is the last date the assessing clinician gathered information used to complete the comprehensive assessment and finished documenting it. It is not necessarily a visit date. If the clinician calls the family or the physician two days after the visit to finish an item, M0090 is the date of that call. It can never be before the start of care date.
What counts as the date of referral for M0104?
The date the agency received a valid referral: enough information about the patient to begin an assessment, plus confirmation that a physician or allowed practitioner will provide the plan of care and ongoing orders. The date a payer authorized services is not the referral date. A call from a family member or a facility to warn you a patient may be coming is not a referral either.
Does the 60-day certification period start on the start of care date?
Yes. The start of care date is day 1 of the first 60-day certification period, and every later period, including the recertification window on days 56 to 60, counts from it. A resumption of care after a hospital stay does not move it.
Sources
- CMS, OASIS-E2 Guidance Manual, effective April 1, 2026, Chapter 3: M0030 (start of care date), M0032 (resumption of care date), M0090 (date assessment completed), M0102 (physician-ordered start of care date), M0104 (date of referral); Chapter 1, Table 1.2 (assessment timeframes). Every quotation above is from the April 2026 final manual.
- CMS, State Operations Manual, Appendix B, tag G520 (interpretive guidelines for 42 CFR 484.55(b)(1)).
- 42 CFR 484.55: (a)(1) initial assessment visit timing, (b)(1) comprehensive assessment within 5 calendar days, (d)(1) recertification window.
- 42 CFR 484.45(a): transmission within 30 days of completing the assessment.
- 42 CFR 484.205(j): Notice of Admission.
- Related on this site: the 48-hour rule, referral to first visit, resumption of care guide, and the OASIS schedule calculator.