CPT® Code 85549

The CPT® Code 85549 refers to a laboratory test that measures the levels of muramidase, which is a bacteriolytic enzyme integral to the innate immune system. Muramidase plays a crucial role in the body's defense mechanisms and is predominantly found in various bodily fluids, including tears, saliva, mucus, human breast milk, and the cytoplasmic granules of polymorphonuclear neutrophils. This enzyme is significant because its serum levels can increase in response to the degradation of polymorphonuclear neutrophils, which may occur in both benign conditions such as infections and inflammation, as well as in malignant diseases like acute or chronic granulocytic or monocytic leukemias, specifically classified as FAB-M4, chronic myelogenous leukemia (CML), and chronic myelomonocytic leukemia (CMML). Additionally, elevated levels of muramidase in serum and urine can indicate severe renal insufficiency, renal transplant rejection, and urinary tract infections. The test can be performed on various samples, including blood, urine, tears, and cerebrospinal fluid, with the blood sample obtained through a separately reportable venipuncture. The urine sample can be collected via random void or catheterization. The quantitative measurement of muramidase levels in serum, urine, tears, and cerebrospinal fluid is conducted using a technique known as quantitative radial immunodiffusion, which allows for precise quantification of this important enzyme.