OASIS Manual · For admins & DONs

M0090, Completion Windows, and Transmission Deadlines

The dates that drive every OASIS — RFA-specific completion windows, the M0090 date, and the 30-day iQIES transmission clock, with the CMS citation for each.

By Reza Djangi, OTR/L·7 min read·Aligned with OASIS-E2 v1.00.0

CMS source

OASIS-E2 Guidance Manual · Verified 2026-10-16

TL;DR

M0090 (Date Assessment Completed) is the date CMS holds up against the completion window, and the date the 30-day transmission clock runs from. iQIES also uses it to decide which version of the data specifications a record is checked against.
Completion windows depend on the RFA: 5 calendar days after the SOC date for SOC; 2 calendar days for ROC, Other Follow-up, Transfer, Death at Home and Discharge; days 56–60 of the 60-day period for Recert.
The CoPs give you 30 days from completing the assessment to transmit it (42 CFR §484.45(a)). A record sent later is still accepted, with a warning.

The 60-day cert at a glance

Timeline

Standard 60-day cert period

Day 0 · RFA 01
Start of Care
OASIS comprehensive assessment must be completed within 5 days after the SOC date.
Day 14 · RFA 03
Resumption of Care window
If the patient returns from a 24+ hour inpatient stay, complete within 2 calendar days.
Day 30 · RFA 06 or 07
Transfer event window
Transfer assessment within 2 calendar days of learning of the transfer.
Day 56 · RFA 04
Recertification window — day 56
Recert OASIS may be completed during the last 5 days of the cert (days 56–60).
Day 60 · RFA 04 or 09
Recert due — day 60
Recert must be completed by day 60 if care continues. A patient who is not continuing is discharged with RFA 09.

What is M0090?

Specifies the actual date the assessment is completed. [...] 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. [...] 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.

Source: OASIS-E2 Guidance Manual — Ch. 3, Section A, M0090, pp. 41–42 · Verified 2026-10-16

From the field

M0090 is one of the fields I see edited most on a finished OASIS. Why? Because someone tries to "fix" a late record by backdating it. Don't. M0090 is the date the assessing clinician finished gathering the information and finished documenting it, not the date a supervisor wishes it had been. CMS says the state survey process may compare the OASIS data you collected with what you encoded and sent, so the visit note and M0090 need to tell the same story. If the note is signed 11/14 and M0090 says 11/12, that is the kind of mismatch a reviewer catches.

The way I think about it: M0090 is the day both halves were done. If the clinician left the home on day 4 with everything gathered but finished documenting the responses on day 5, M0090 is day 5. If they called the family on day 5 to answer an item the patient could not, M0090 is day 5 too, even with no visit that day. And if QA later finds an error, you correct it under your agency's correction policy. M0090 does not have to move.

Completion windows per assessment type

OASIS data are collected at the time points listed in the table below, and within the required assessment timeframe. Not all OASIS items are completed at every assessment time point.

Source: OASIS-E2 Guidance Manual — Ch. 1, §1.5.5, p. 10 · Verified 2026-10-16

The assessment timeframe column of that table (Table 1.2), as CMS prints it:

Time point	M0100	Assessment timeframe
Start of Care	1	Within 5 calendar days after the SOC date (SOC = Day 0)
Resumption of Care	3	Within 2 calendar days of the facility discharge date, or knowledge of the patient's return home
Recertification (follow-up)	4	The last 5 days of every 60 days (i.e., days 56-60 of the current 60-day period)
Other follow-up	5	Within 2 calendar days of significant change in patient's condition.
Transfer	6, 7	Within 2 calendar days of the discharge/transfer/death date, or knowledge of a qualifying transfer to an inpatient facility
Death at Home	8	Within 2 calendar days of the discharge/transfer/death date.
Discharge	9	Within 2 calendar days of the discharge/transfer/death date.

When the recert window is missed

If an agency misses the recertification assessment time frame (days 56-60 of the current 60-day certification period), the agency should not discharge and readmit the patient (i.e., complete a new SOC). Rather, the agency should send a clinician to perform the recertification assessment as soon as the oversight is identified. The date assessment completed (M0090) should be reported as the actual date the assessment is completed, with documentation in the clinical record of the circumstances surrounding the late completion. When submitting the assessment, a warning message will result from the non-compliant assessment date, but this will not prevent assessment transmission.

Source: OASIS-E2 Guidance Manual — Ch. 3, Section A, M0100, p. 46 · Verified 2026-10-16

The 30-day transmission rule

The deadline is in the Conditions of Participation, not the guidance manual. 42 CFR §484.45(a) says an HHA must encode and transmit each completed OASIS assessment "within 30 days of completing the assessment of the beneficiary."

Fixing a record after iQIES has accepted it

Effective January 1, 2020, HHAs have 24 months from the assessment target date to submit, modify, or inactivate OASIS records.

Source: OASIS-E2 Guidance Manual — Ch. 2, §2.4, p. 18 · Verified 2026-10-16

Common errors

OASIS Assessment Schedule — which assessments have which windows
QA Workflow and Corrections — correcting records before and after transmission
Submitting OASIS to iQIES — the transmission process step by step