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Layer 1 extracts the state code from the first two digits of a CCN and resolves all location-dependent billing context. This is the foundation layer — every other layer builds on it.

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How it works

A CCN’s first two digits encode the state:
From the state, L1 resolves geographic adjustments (GPCI), the Medicare Administrative Contractor (MAC) that processes claims, the state Medicaid program, and filing deadlines.

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Request

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Response

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What L1 resolves

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GPCI values explained

The Geographic Practice Cost Index adjusts Medicare’s national RVU values for local cost differences: A GPCI of 1.0 means equal to the national average. Kansas has a Work GPCI floor of 1.000, a PE GPCI of 0.904 (9.6% below average), and a very low MP GPCI of 0.504 (malpractice is cheap in Kansas).
GPCI values are updated annually by CMS from the Physician Fee Schedule Relative Value Files. L6 uses these values automatically when calculating payment.

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MAC jurisdictions

The Medicare Administrative Contractor (MAC) determines where claims are submitted and which LCD/NCD policies apply: Knowing your MAC matters because Local Coverage Determinations (LCDs) vary by jurisdiction. A service covered under one MAC may have different documentation requirements under another.

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State code reference

Common state codes used in CCNs:
State codes in CCNs are not the same as FIPS codes or postal abbreviations. State code 17 is Kansas (not Illinois). Always use the CCN parser to decode — don’t assume.