85540 Wbc alkaline phosphatase
Also known as: LAP score, leukocyte alkaline phosphatase
Measurement of leukocyte alkaline phosphatase (LAP) activity in white blood cells using histochemical staining and microscopy to assess neutrophil activation status.
In Plain Language
white blood cell enzyme activity test; neutrophil activation test
Clinical Context
Differentiates chronic myeloid leukemia (low LAP) from leukemoid reaction (high LAP); largely replaced by cytogenetics and molecular testing.
RVU Information
CPT 85540 does not have a physician work RVU assigned by CMS. Reimbursement for this code is determined by payer-specific fee schedules.
Billing & Documentation
Lab and pathology codes require an order from the treating provider with clinical indication. For molecular pathology and genetic testing, document the specific analytes tested and clinical rationale.
How This Code Compares
This code has a work RVU of 0.00, meaning it does not have a physician work component assigned by CMS. In the Pathology & Lab category, 94% of codes share this characteristic.
Specialties
Frequently Asked Questions
What is CPT code 85540?
CPT 85540 (Wbc alkaline phosphatase) is a Pathology & Lab code. Measurement of leukocyte alkaline phosphatase (LAP) activity in white blood cells using histochemical staining and microscopy to assess neutrophil activation status.
Who uses CPT code 85540?
CPT 85540 is used by Clinical Pathology, Hematology, Oncology. Differentiates chronic myeloid leukemia (low LAP) from leukemoid reaction (high LAP); largely replaced by cytogenetics and molecular testing.
When is CPT 85540 used?
Differentiates chronic myeloid leukemia (low LAP) from leukemoid reaction (high LAP); largely replaced by cytogenetics and molecular testing.
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CPT® is a registered trademark of the American Medical Association. Data sourced from CMS Physician Fee Schedule RVU26A. Descriptions, synonyms, and clinical context are original content by RVU Edge.