Summary & Overview
CPT 85598: Hexagonal Phase Phosphatidylethanolamine Clotting Assay
CPT code 85598 designates a specialized coagulation assay in which hexagonal phase phosphatidylethanolamine is added to a blood specimen to evaluate clotting time. This assay is used to detect specific clotting abnormalities and can inform diagnosis and management of clotting disorders. Nationally, accurate coding of this procedure supports appropriate laboratory billing, surveillance of coagulation testing utilization, and consistent clinical documentation.
Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the clinical context for the assay, typical sites of service, and the payer landscape relevant to coverage and billing. The publication also summarizes common modifiers and highlights where data is not available in the input.
This piece provides clinicians, billing professionals, and policy analysts with a focused briefing on the code's clinical purpose, typical use settings, and what aspects of coverage and policy to consider when encountering CPT code 85598 in practice. Data not available in the input is explicitly noted where applicable.
Billing Code Overview
CPT code 85598 describes a laboratory procedure in which a lab analyst evaluates clotting time after adding a reagent called hexagonal phase phosphatidylethanolamine to a patient blood specimen. This test is a specialized coagulation assay used to detect abnormalities in clot formation influenced by the specific reagent.
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Service type: Specialized laboratory coagulation assay
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Typical site of service: Clinical laboratory or hospital laboratory
Data not available in the input.
Clinical & Coding Specifications
Clinical Context
A typical patient is an adult with a history of unexplained venous or arterial thrombosis, recurrent pregnancy loss, or a thrombotic event while on anticoagulation who is being evaluated for antiphospholipid antibodies and a potential lupus anticoagulant. The laboratory receives a citrated plasma specimen from the outpatient hematology clinic or the hospital inpatient unit. The technologist performs coagulation screening tests (prothrombin time, activated partial thromboplastin time) and reflexes to specialized assays when a prolonged clotting time is detected. For this procedure, the lab analyst performs the hexagonal phase phosphatidylethanolamine neutralization test to assess for a lupus anticoagulant by adding the hexagonal phase reagent to the patient specimen and measuring clotting time changes. Results are reviewed by a clinical pathologist or hematologist, reported in the electronic medical record, and used by the ordering clinician to guide diagnosis of antiphospholipid syndrome and subsequent management planning, such as anticoagulation decisions or additional serologic testing.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when reporting the physician or pathologist professional interpretation component separate from the technical laboratory component. |
TC |