How to Test X12 270/271 EB: A Field-by-Field Breakdown
EQ asks the question on a 270 inquiry. EB is the answer that comes back on the 271 — and it is almost always the segment your intake or eligibility-check logic actually parses, because it is where the deductible, the copay, the coinsurance percentage, and the active/inactive status all live.
EB (Subscriber/Dependent Eligibility or Benefit Information) is the response segment in an X12 271 that reports coverage status and benefit detail for a specific service type — whether coverage is active, what the deductible or out-of-pocket amount is, and what percentage the plan covers.
The elements that actually matter in practice
Example
C = deductible, IND = individual coverage, service type 30 = general health benefit plan, plan name Acme PPO Bronze, EB06 27 = remaining, EB07 500.00 is the dollar amount, EB09 22 = social security number qualifier slot left blank. Synthetic 271 response data.
Where this trips people up
A single 271 response routinely carries a dozen or more repeated EB segments, one per service type and benefit combination, and several will share the same EB01 value with different EB03 service types. Parsers built to grab the "first EB segment" for a quick active/inactive check often end up reading a dental or vision line instead of the medical one, and testers rarely notice because the code that matters most, EB01, still looks correct.