Why Pharmacy Claims Still Use a Binary Protocol from the 90s (And How to Fix It)

Every time you pick up a prescription, a pharmacy claim gets submitted to your insurance. That transaction travels through a system built in the 1990s — a binary, pipe-delimited protocol called NCPDP Telecommunication Standard D.0.

Here's what a pharmacy claim looks like on the wire:

\x1E\x1CAM04\x1CC4197103141\x1CC51\x1CC601\x1CCA01234567890

Those hex characters are segment separators. The spec has over 400 field definitions. Every pharmacy system in the country encodes and decodes this format. Get one byte wrong and the claim gets rejected.

Why it's still like this

The pharmacy claims network is a chain: pharmacy → switch → PBM. Every link speaks NCPDP D.0. Changing the protocol means coordinating thousands of pharmacies, dozens of switches, and hundreds of PBMs simultaneously. Nobody wants to go first.

The switches (Change Healthcare, SS&C, etc.) act as routers. They read the BIN number from the claim and forward it to the right PBM. Connecting to a switch requires:

1. A contract and NDA


2. VPN or dedicated line connectivity


3. NCPDP binary protocol implementation


4. Certification testing


5. Per-payer field requirement maintenance

This takes 3-6 months and dedicated healthcare engineers.

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