# CPT 83550

> Not at a published national rate. CPT 83550 carries status X (statutory exclusion) in the Q4 2016 release. The statutory definition of physician services does not include this item. Treat the blank amount as unpriced, not as $0.

## What it is

Measures how much iron the blood's carrier proteins could hold if they were completely loaded - the binding capacity - or, in some laboratories, the portion of that capacity currently sitting empty. It works as a stand-in for how much transferrin, the iron transport protein, is available. Its real value comes from pairing it with a serum iron result, which lets the lab calculate what percentage of the carrying capacity is actually in use; that saturation figure describes iron status far better than either number by itself.

## Selected release

- Release: Q4 2016 (2016 D)
- Effective: October 1 – December 31, 2016
- Status indicator: X
- Office (non-facility) national allowed amount: not published
- Facility national allowed amount: not published
- Sequestration: not applied

## RVUs and formula

- Work RVU: not published
- Office (non-facility) practice expense RVU: not published
- Facility practice expense RVU: not published
- Malpractice RVU: not published
- Conversion factor: 35.8043
- Formula: `(work_rvu × work_gpci + pe_rvu × pe_gpci + mp_rvu × mp_gpci) × conversion_factor`

## Source and citation

- Source: Physician relative value file (Q4 2016)
- CMS file: https://www.cms.gov/medicare/medicare-fee-for-service-payment/physicianfeesched/downloads/rvu16d.zip
- Parsed file: PPRRVU16_V0804.csv, row 13,646
- Canonical page: https://localishealth.com/cpt/83550/2014/B
- Release-specific citation URL: https://localishealth.com/cpt/83550/2016/D
- Last significant update: 2026-08-04T03:07:13+00:00