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Test ID LKM Liver/Kidney Microsome Type 1 Antibodies, Serum

Reporting Name

Liver/Kidney Microsome Type 1 Ab, S

Useful For

Evaluation of patients with liver disease of unknown etiology


Evaluation of patients with suspected autoimmune hepatitis

Specimen Type


Specimen Required


Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL

Specimen Minimum Volume

0.4 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 21 days
  Frozen  21 days

Reference Values

≤20.0 Units (negative)

20.1-24.9 Units (equivocal)

≥25.0 Units (positive)

Reference values apply to all ages.

Day(s) Performed

Monday, Wednesday, Friday

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
LKM Liver/Kidney Microsome Type 1 Ab, S 32220-6


Result ID Test Result Name Result LOINC Value
LKM Liver/Kidney Microsome Type 1 Ab, S 32220-6

Clinical Information

Autoimmune liver disease (eg, autoimmune hepatitis and primary biliary cirrhosis) is characterized by the presence of autoantibodies including smooth muscle antibodies (SMA), antimitochondrial antibodies (AMA), and anti-liver/kidney microsomal antibodies type 1 (anti-LKM-1).(1) Subtypes of autoimmune hepatitis (AIH) are based on autoantibody reactivity patterns.


Anti-LKM-1 antibodies serve as a serologic marker for AIH type 2 and typically occur in the absence of SMA and antinuclear antibodies. These antibodies react with a short linear sequence of the recombinant antigen cytochrome monooxygenase P450 2D6.(2) Patients with AIH type 2 more often tend to be young, female, and have severe disease that responds well to immunosuppressive therapy.


Seropositivity for anti-liver/kidney microsomal antibodies type 1 (anti-LKM-1) antibodies is consistent with a diagnosis of autoimmune hepatitis (AIH) type 2.

Clinical Reference

1. Clinical Immunology Principles and Practice. Third edition. Edited by RR Rich, TA Fliesher, WT Shearer, et al: Philadelphia, PA, Mosby Elsevier, 2008

2. Czaja AJ, Homburger HA: Autoantibodies in liver disease. Gastroenterology. January 2001;120(1):239-249

Report Available

1 to 4 days

Method Name

Enzyme-Linked Immunosorbent Assay (ELISA)


If not ordering electronically, complete, print, and send a Gastroenterology and Hepatology Client Test Request (T728) with the specimen.