# CPT 84100

> Not at a published national rate. CPT 84100 carries status X (statutory exclusion) in the Q2 2015 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 inorganic phosphate in the blood. Phosphate is cleared by the kidneys and regulated in tandem with calcium, vitamin D, and parathyroid hormone, so it climbs as kidney function fails and falls with malnutrition, with overactive parathyroid glands, and in the first days of feeding someone who has been starved. It is a routine part of monitoring people with chronic kidney disease and those on dialysis, where a persistently high level drives bone and blood-vessel damage.

## Selected release

- Release: Q2 2015 (2015 B)
- Effective: April 1 – June 30, 2015
- 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: 35.7547
- Formula: `(work_rvu × work_gpci + pe_rvu × pe_gpci + mp_rvu × mp_gpci) × conversion_factor`

## Source and citation

- Source: Physician relative value file (Q2 2015)
- CMS file: https://www.cms.gov/medicare/medicare-fee-for-service-payment/physicianfeesched/downloads/rvu15b.zip
- Parsed file: PPRRVU15_V0213_Current.csv, row 13,480
- Canonical page: https://localishealth.com/cpt/84100/2014/B
- Release-specific citation URL: https://localishealth.com/cpt/84100/2015/B
- Last significant update: 2026-08-04T03:05:48+00:00