Summary & Overview
CPT 83670: Leucine Aminopeptidase Enzyme Assay
CPT code 83670 represents a laboratory test that measures leucine aminopeptidase enzyme activity, commonly used to detect liver cell injury or hepatic tumors. Nationally, this biochemical assay is relevant to hospital and outpatient laboratory workflows and to clinical decision-making when assessing possible hepatobiliary disease. The code informs billing for a specific enzymatic assay rather than broader metabolic panels.
Key payers in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the clinical context for the test, the typical settings where the service is performed, and the payer landscape covered. The publication highlights benchmarking metrics, common billing and billing practice considerations, and any recent policy or coverage changes affecting laboratory enzymatic assays when available.
This summary provides clinicians, laboratory managers, and billing professionals with the essential facts about the code, its clinical significance, and what to expect in payer coverage discussions. Data not available in the input will be noted in relevant sections of the full publication.
Billing Code Overview
CPT code 83670 describes a laboratory assay that measures the activity level of leucine aminopeptidase, an enzyme present in small intestine and liver cells. Elevated levels of this enzyme can indicate liver injury or hepatic tumor.
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Service type: Clinical laboratory biochemical assay measuring enzyme activity
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Typical site of service: Hospital laboratory, independent clinical laboratory, or outpatient laboratory collection site
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Clinical & Coding Specifications
Clinical Context
A typical patient is an adult presenting to an outpatient clinic or hospital with symptoms suggesting hepatobiliary disease (eg, jaundice, right upper quadrant pain, abnormal liver function tests) or as part of a workup for suspected liver metastasis or hepatocellular injury. The clinician orders a serum leucine aminopeptidase test when evaluation of hepatic enzyme patterns is needed to help distinguish hepatic versus bone sources of elevated alkaline phosphatase or to support evidence of liver cell injury or tumor. A phlebotomist collects a blood specimen and sends it to the clinical laboratory. A medical technologist or lab analyst performs the 83670 assay on the specimen using the laboratory’s validated biochemical method, documents results in the laboratory information system, and issues a report to the ordering provider. Results are interpreted in the context of other liver function tests (eg, AST, ALT, alkaline phosphatase, bilirubin) and clinical findings; elevated leucine aminopeptidase suggests liver cell damage or tumor and may prompt further imaging or specialty referral.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when billing only the professional interpretation component if the lab sends out interpretation separate from technical processing. |