Summary & Overview
CPT 84087: Phosphohexose Isomerase (GPI) Assay
CPT code 84087 denotes a laboratory assay for phosphohexose isomerase (PHI), also known as glucose phosphate isomerase (GPI). This biochemical test is used to evaluate enzyme levels in patient specimens, typically blood, and can inform diagnostic and monitoring decisions in conditions where PHI/GPI measurement is clinically relevant. Nationally, CPT 84087 matters as part of the spectrum of specialty enzymatic tests performed by clinical and hospital laboratories, with implications for coding accuracy, billing, and laboratory service coverage.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of clinical context for the assay, typical sites of service, common billing modifiers listed in the input, and guidance on where to locate additional payer-specific policy language. The publication summarizes common reimbursement considerations, coding description, and operational implications for laboratories processing this test.
This summary is intended to inform laboratory administrators, billing professionals, and policy analysts about the clinical purpose of CPT 84087, payer landscape coverage references, and the types of benchmarks and policy updates to review when managing claims and coverage for specialized enzymatic assays.
Billing Code Overview
CPT code 84087 describes a laboratory assay that measures phosphohexose isomerase (PHI), also known as glucose phosphate isomerase (GPI), in a patient specimen such as blood. The test quantifies the level of this enzyme to assist clinical evaluation where measurement of PHI/GPI is indicated.
Service type: Clinical laboratory diagnostic test
Typical site of service: Clinical laboratory or hospital laboratory
Clinical & Coding Specifications
Clinical Context
A typical patient is an adult referred for a laboratory evaluation of suspected hemolytic anemia or a hereditary enzyme deficiency after abnormal routine testing. The ordering clinician (often a hematologist or primary care physician) requests measurement of phosphohexose isomerase (PHI/GPI) activity on a fresh blood specimen to evaluate red blood cell enzyme function or to investigate unexplained anemia, chronic hemolysis, or suspected metabolic disorder. The clinical workflow: the patient presents for venipuncture at an outpatient laboratory or hospital phlebotomy station (common sites of service: outpatient laboratory, hospital clinical laboratory, or specialty reference laboratory). The specimen is collected in the appropriate tube, labeled, and transported under required temperature conditions to the lab. A medical laboratory scientist or clinical chemist performs the enzymatic assay, documents results in the laboratory information system, and the ordering provider interprets results in the context of clinical findings and other laboratory data. Results may prompt additional genetic testing or hematology referral.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when billing only the professional component (interpretation) of the test if separated from technical work |
TC |