X12 270/271 EB01 Field Guide: Eligibility or Benefit Information Codes and Common Mistakes
EB01 is one character that a front-desk eligibility check hangs its entire decision on. Read it as a simple yes/no and you will misroute patients whose plan is active but who happen to be past their deductible or capped on visits.
EB01 is the first element of the EB segment in an X12 271 response — a single code that states what kind of eligibility or benefit information the rest of the segment describes, such as active coverage, inactive coverage, a deductible amount, or an out-of-pocket limit.
Valid code values
Example
EB01 = C tells the reader this line reports a deductible, so the amount in EB07 (500.00) should be read as a deductible balance, not a copay. Synthetic 271 response data.
Where this trips people up
A test suite that only checks for EB01 = 1 versus "anything else" treats a deductible line (C) or a coinsurance line (A) the same as an outright denial. Those are informational segments describing an active plan's cost-sharing, not eligibility failures, and flagging them as denials generates false rejections that front-desk staff learn to ignore, which is worse than no check at all.