CPT: 85549
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Test Details


  • Muramidase, Serum


Differential diagnosis of leukemia. Present in association with some cases of myelogenous leukemia and in most cases of monocytic leukemia.


Test may lack specificity when applied to classification of acute leukemia (occasional false-positive cases of M1, M2, and M6).1



Reference Interval

Male: 3.0−12.8 μg/mL; female: 2.5−12.9 μg/mL

Additional Information

Serum lysozyme has been proposed as a parameter for monitoring disease progression/regression in cases of proven sarcoidosis.2 Revised FAB (French, American, British) criteria indicate that serum or urine lysozyme levels 3x normal fulfill one of three criteria for the presence of M4/M5 (acute myeloid leukemia with monocytic differentiation) vs M2 (acute myeloblastic leukemia with maturation).

Lysozyme, a hydrolytic enzyme and bacteriolytic glycosidase, when present in large amounts may appear as a far cathodal migrating (“cationic”) band on serum or urine protein electrophoresis. Lysozyme has been found in all three human neutrophil granules (azurophil, specific, and gelatinase types).3 It is elevated in some cases of myelogenous and in most cases of myelomonocytic and monocytic leukemia. The elevation is proportional to the degree of monocytic differentiation and to tumor cell burden and, if marked, can result in potassium wasting and hypokalemia.4 Lysozyme has been found within the granules of normal and leukemic eosinophils by immunoelectron microscopic study. Elevated serum lysozyme may not establish the presence of monocytic differentiation in cases of acute myelogenous leukemia with eosinophilia.5 The level of serum lysozyme has been used as a predictor of CNS involvement in these leukemias.6

Serum lysozyme has been shown to be elevated in a number of conditions, including tuberculosis and sarcoidosis as well as leukemia.2 Sensitivity for prediction of sarcoidosis was 79% in a recent study (compare that of serum angiotensin-converting enzyme (ACE) at 59% in the same study).2 The serum lysozyme level increased with the number of organs involved. Serum lysozyme, however, is less specific for sarcoidosis than serum ACE. When utilizing a turbidimetric method for measurement of serum lysozyme activity, there was evidence that such an assay was useful in differentiating infection from rejection in transplant recipients.7

Specimen Requirements




1 mL

Minimum Volume

0.2 mL


Red-top tube or gel-barrier tube


Transfer specimen to a plastic transport tube before shipment.

Storage Instructions

Room temperature.

Stability Requirements



Room temperature

4 days


4 days


14 days

Freeze/thaw cycles

Stable x2

Clinical Information

Special Instructions

State patient's sex on the test request form.


1. Sexton C, Buss D, Powell B, et al. Usefulness and limitations of serum and urine lysozyme levels in the classification of acute myeloid leukemia: An analysis of 208 cases. Leuk Res. 1996 Jun; 20(6):467-472. 8709618
2. Tomita H, Sato S, Matsuda R, et al. Serum lysozyme levels and clinical features of sarcoidosis. Lung. 1999; 177(3):161-167. 10192763
3. Lollike K, Kjeldsen L, Sengelov H, Borregaard N. Lysozyme in human neutrophils and plasma. A parameter of myelopoietic activity. Leukemia. 1995 Jan; 9(1):159-164. 7845012
4. Hillman RS, Ault KA. The acute myeloid leukemias. Hematology in Clinical Practice: A Guide to Diagnosis and Management. 2nd ed. New York, NY: McGraw-Hill, Health Professions Division;1998:274:chap 17.
5. Moscinski LC, Kasnic G Jr, Saker A Jr. The significance of an elevated serum lysozyme value in acute myelogenous leukemia with eosinophilia. Am J Clin Pathol. 1992 Feb; 97(2):195-201. 1546687
6. Peterson BA, Brunning RD, Bloomfield CD. Central nervous system involvement in acute nonlymphocytic leukemia. A prospective study of adults in remission. Am J Med. 1987 Sep; 83(3):464-470. 3661583
7. Jones JW Jr, Su S, Jones MB, Heniford BT, McIntyre K, Granger DK. Serum lysozyme activity can differentiate infection from rejection in organ transplant recipients. J Surg Res. 1999Jun 15; 84(2):134-137. 10357909


Wickenhauser C, Thiele J, Schmitz B, et al. Polycythemia vera megakaryocytes store and release lysozyme to a higher extent than megakaryocytes in secondary polycythemia (polyglobuly). Leuk Res. 1999 Mar; 23(3):299-306. 10071085
Wolach B, Gavrieli R, Manor Y, Lishner M. Leukocyte function in chronic myeloproliferative disorders. Blood Cells Mol Dis. 1998 Dec; 24(4):544-551. 9887281


Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
080713 Lysozyme, Serum 2589-0 080713 Lysozyme, Serum ug/mL 2589-0

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