Reading the 278 response
The 278 response carries an action code that is the decision. There are five values a practice sees regularly, and the difference between them determines whether you can proceed, whether you must act, and how long you have.
| Code | Meaning | What it actually requires of you |
|---|---|---|
| A1 | Certified in total | Approved as requested. Record the number, the effective dates and the approved units. Nothing further until the service. |
| A2 | Certified in part | Some of what you asked for was approved and some was not. Read the detail: fewer units, a shorter window, or one of several codes refused. Proceeding as though this were A1 produces an unauthorized service. |
| A3 | Not certified | Denied. An appeal clock starts now. See Denials and appeals. |
| A4 | Pended | Not a decision. Review is continuing. This is where requests are lost. |
| A6 | Modified | Approved as something other than what you asked. A different code, a different setting, a different quantity. Treat as a new fact, not an approval. |
The two that get misread
A2 and A6 both contain the word approved in conversation and neither approves what you requested. A partial certification for six units when you asked for twelve means the seventh unit is unauthorized. A modification to a less intensive setting means the setting you booked is unauthorized. Both are frequently filed as approvals and discovered at the claim.
#What else the response carries
The certification number- The identifier that has to reach the claim. This is the single most valuable field in the response.
Effective and expiration dates- The window the approval is good for. A service outside it is unauthorized even though an authorization exists. Approvals expire and the expiry is rarely prominent.
Approved quantity- Units, visits or days. Compare against what you requested every time rather than assuming.
Reason codes- On a denial or a pend, why. Under CMS-0057-F, impacted payers must give a specific reason for a denial, which is intended to make resubmission or appeal possible rather than guesswork.
#A 202 is not an approval
When submitting through an API rather than batch EDI, a common pattern is that the submission is accepted with an HTTP 202 and an empty body, and the decision is retrieved by polling. A 202 means the request reached the queue. It says nothing about the outcome.
Systems that treat a successful submission as a successful authorization are a recognised failure mode, and the consequence is a procedure that goes ahead on an authorization that was never granted. Poll until there is an action code.
Record what you were told, not what you concluded
Store the action code, the certification number, the dates and the approved quantity as separate fields rather than as a note saying approved. Everything downstream, from the claim to the appeal, needs the specifics, and a note cannot be checked against a service date automatically.