What an Eligibility Check Actually Asks

Most people in behavioral health billing learn the 270/271 transaction the same way: someone hands them a clearinghouse login and says “run eligibility.” Here is what is actually happening inside the envelope.

The question (270)

An ANSI X12 270 is an inquiry. It carries the payer identity, the provider identity, the member’s identifier and date of birth, and the date of service being asked about. Strip away the segment syntax and it is one question: is this person covered on this date, by this plan, and what does the payer say the benefit looks like.

The answer (271)

A 271 comes back as eligibility or rejection. When it is eligibility, three things matter more than the rest:

• Coverage dates. Active, termed or pending — and whether the date of service sits inside them.
• Cost share. Copay, coinsurance, deductible remaining, and whether a spend-down applies.
• Network attribution. Which regional entity the member is assigned to, and which network counts as in-network for the service.

In Colorado Medicaid that third item is the one people underestimate. Regional attribution decides which contract pricing applies, and getting it wrong is how a clean eligibility response still turns into a denial later.

Real-time versus batch

Real-time is a round trip per inquiry — fine for a handful of clients, terrible for a roster. Batch is a file in and a file out: fast, but it leaves you reconciling line-level errors from a response you did not watch happen. Same transaction. The difference is who is waiting.

Why this should never be manual

An eligibility check is deterministic: same input, same question, same shape of answer. Anything deterministic with a structured response belongs in a pipeline, not in someone’s afternoon. A pipeline does not misread a date, does not skip the log, and does not lose the response for the one client who gets audited six months later.

Understand the question you are asking and the answer stops being intimidating.

This is the part I get hired for

Everything above is deterministic: same input, same question, same shape of answer. A human reading it is the only variable. I build AI-assisted automation for behavioral health billing — real-time 270/271 eligibility, RAE regional attribution, contractual rate lookup, and batch runs that reconcile line-level errors instead of leaving you to read a response you never watched happen.

I’m August Casso — self-taught systems engineer, web developer, and AI prompt analyst working in Colorado Medicaid and Change Healthcare APIs daily. If your team is still hand-keying eligibility one client at a time, that is the exact bottleneck I take on.

Hire me: casso@aug.quest  ·  What I actually do