Summary & Overview
CPT 84590: Vitamin A Assay, Laboratory Test
CPT code 84590 identifies a laboratory assay that measures vitamin A levels in a patient specimen, most commonly blood. This test is clinically important for diagnosing and monitoring vitamin A deficiency or excess, informing nutritional management and certain disease evaluations. As a standardized CPT laboratory code, 84590 is used across clinical and hospital laboratory settings and plays a consistent role in outpatient and inpatient diagnostic workflows.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the code’s clinical context, expected site-of-service usage, and typical billing considerations relevant to national payers. The publication summarizes common modifiers and administrative notes when available, highlights how this test fits into clinical pathways for nutritional assessment, and outlines where to find related billing guidance.
The content is intended to help billing managers, laboratory directors, and clinical coders understand the purpose of CPT code 84590, the settings where it is typically performed, and the administrative elements that often accompany its use. Data not available in the input is noted where applicable.
Billing Code Overview
CPT code 84590 describes a laboratory assay performed by a lab analyst to measure the amount of vitamin A in a patient specimen, typically blood. This service is a clinical laboratory test used to assess vitamin A status for diagnostic, monitoring, or nutritional evaluation purposes.
-
Service type: Clinical laboratory assay
-
Typical site of service: Clinical laboratory or hospital laboratory (specimen collected in an outpatient clinic or phlebotomy setting and analyzed in a lab)
Data not available in the input for associated taxonomies, ICD-10 diagnoses, or related codes.
Clinical & Coding Specifications
Clinical Context
A typical patient is an adult or pediatric outpatient referred by a primary care provider or pediatrician for assessment of nutritional status, malabsorption, or suspected vitamin deficiency. The clinician orders a serum vitamin A (retinol) level when patients present with symptoms such as night blindness, xerosis, unexplained weight loss, chronic diarrhea, fat malabsorption (for example from celiac disease or post-bariatric surgery), or when monitoring patients on long-term total parenteral nutrition or high-dose vitamin A therapy. The clinical workflow: the provider places the laboratory order for 84590; the patient presents to an outpatient laboratory, hospital phlebotomy service, or clinic phlebotomy area (typical site of service: outpatient laboratory or hospital outpatient blood draw). A phlebotomist collects a venous blood specimen, which is sent to the clinical chemistry or reference laboratory. The laboratory analyst performs quantitative measurement of serum retinol by appropriate analytic method (e.g., HPLC or mass spectrometry), documents results in the laboratory information system, and the ordering provider reviews results in the electronic medical record to guide clinical management such as nutritional counseling, supplementation, or further evaluation for malabsorption or liver dysfunction.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | When billing for the physician or pathologist interpretation component separate from the technical laboratory work, if applicable. |