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HelpTest ID LKM Liver/Kidney Microsome Type 1 Antibodies, Serum
Specimen Required
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions: Centrifuge and aliquot serum into a plastic vial.
Forms
If not ordering electronically, complete, print, and send Gastroenterology and Hepatology Test Request (T728) with the specimen:
Secondary ID
80387Useful For
Evaluation of patients with liver disease of unknown etiology
Evaluation of patients with suspected autoimmune hepatitis
Method Name
Enzyme-Linked Immunosorbent Assay (ELISA)
Reporting Name
Liver/Kidney Microsome Type 1 Ab, SSpecimen Type
SerumSpecimen Minimum Volume
0.4 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 21 days | |
| Frozen | 21 days |
Clinical Information
Autoimmune hepatitis (AIH) is a form of chronic liver disease that results from a loss of immune system tolerance and recognition of self-antigens.(1) AIH occurs in children and adults, with a significant female predominance. The clinical presentation of AIH varies significantly from asymptomatic liver dysfunction to acute liver failure. Evidence of liver dysfunction manifests as elevated aspartate aminotransferase, alanine aminotransferase, and gamma glutaryl transferase in the context of normal alkaline phosphatase. In addition, most individuals with AIH display increased concentrations of total IgG.
AIH is associated with the production of autoantibodies, which also serves to subcategorize patients.(2) AIH type I is characterized by the presence of antinuclear antibodies (ANA) and smooth muscle antibodies (SMA). AIH type I is associated with anti-liver/kidney microsomal-1 (LKM-1) and anti-liver cytosol-1 antibodies. AIH type I occurs in children and adults and usually has a relatively mild course that is responsive to steroids and azathioprine. In contrast, AIH type 2 occurs predominantly in children, with a more moderate/severe disease course.
Most of the autoantibodies associated with AIH were originally detected and characterized by indirect immunofluorescence (IIF).(3) Anti-LKM-1 antibodies can be detected by IIF using rodent stomach/liver/kidney composite tissue; anti-LKM-1 antibodies display staining of the proximal tubules in the kidney and cytoplasmic staining of the hepatocytes, with no reactivity on the stomach tissue. The antigen for anti-LKM-1 antibodies has been identified as cytochrome P450 2D6, which has led to the development of solid-phase and bead-based immunoassays.
Although not diagnostic in isolation, the various autoantibodies play an important part in establishing the diagnosis of AIH. Simplified diagnostic criteria for AIH include autoantibodies (ANA, SMA, anti-LKM-1, and anti-SLA), IgG concentrations, histopathology, and evaluation for viral hepatitis, with a scoring system to define probable or definite AIH.(4)
Reference Values
≤20.0 Units (negative)
20.1-24.9 Units (equivocal)
≥25.0 Units (positive)
Reference values apply to all ages.
Cautions
Serologic tests for autoantibodies, including anti-liver/kidney microsomal antibodies type 1 (anti-LKM-1), should not be relied upon exclusively to determine the etiology or prognosis of patients with liver disease.
Anti-LKM-1 antibodies are not the only serological marker for autoimmune hepatitis (AIH) and should be evaluated in the context of other AIH-associated autoantibodies, including antinuclear antibodies and smooth muscle antibodies.
Anti-LKM-1 antibodies may occur in some patients with chronic hepatitis caused by hepatitis C virus (HCV) infection. Although the epitopes recognized by anti-LKM-1 antibodies in HCV infection are different than in patients with AIH type 2, physicians must use caution in interpreting the results of tests for anti-LKM-1 antibodies in such patients.
Day(s) Performed
Monday, Wednesday, Friday
Report Available
2 to 4 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
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
86376