Lysozyme (Muramidase), Plasma

Use

Lysozyme is a bacteriolytic enzyme primarily present in granulocytes, monocytes, and histiocytes, with plasma levels reflecting turnover of these cells. It serves as a screening test for ocular sarcoidosis, confirms marked increases in granulocyte or monocyte pools as in granulocytic or monocytic leukemias, myeloproliferative disorders, and malignant histiocytosis, and is useful for following the course of therapy in chronic granulocytic or chronic monocytic leukemias. Levels may also be elevated in infection, inflammation, kidney disorders, Crohn disease, and kidney transplant rejection — and may be depressed in lymphocytic leukemia. Reference ranges: ≥12 months: 2.6–6.0 mcg/mL; levels above ~200 mcg/mL may indicate acute nonlymphocytic leukemias (M2, M4, M5) or chronic granulocytic leukemias.