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Epic Test Code LAB3805 Liver/Kidney Microsome Type 1 Antibodies, Serum

Additional Codes

MML Code: LKM

LIS Code: LKMAB

NY State Approved

Yes

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Reporting Name

Liver/Kidney Microsome Type 1 Ab, S

Method Name

Enzyme-Linked Immunosorbent Assay (ELISA)

Specimen Stability Information

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


Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

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.


Specimen Type

Serum

Specimen Minimum Volume

0.4 mL

Reference Values

≤20.0 Units (Negative)

20.1-24.9 Units (Equivocal)

≥25.0 Units (Positive)

Reference values apply to all ages.

Report Available

2 to 4 days

Day(s) Performed

Monday, Wednesday, Friday

CPT Code Information

86376

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus OK
Heat treated Reject

Useful For

Evaluation of patients with liver disease of unknown etiology

 

Evaluation of patients with suspected autoimmune hepatitis

Clinical Information

Autoimmune hepatitis (AIH) is 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 diverse autoantibodies which also serves to subcategorize patients.(2) AIH type 1 is associated with F-actin reactive smooth muscle autoantibody (SMA), antinuclear autoantibody (ANA) (60% of patients), and autoantibody to SLA/LP (15% to 20% of patients), while AIH type 2 is associated with LKM-1 and LC-1 autoantibodies.(3) 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).(4) 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 major target for anti-LKM-1 antibodies is the cytochrome P450 2D6 (CYP2D6).(5) Following the identification of this autoantibody target, a number of solid-phase immunoassays have been developed for the evaluation of anti-LKM-1 antibodies.

 

Although not diagnostic in isolation, the presence of certain autoantibodies has been reported to be important in establishing the diagnosis of AIH. Published diagnostic criteria for AIH which include testing for autoantibodies (ANA, SMA, anti-LKM-1, and anti-SLA), determination of serum immunoglobulin, histopathology, evaluation for viral hepatitis, and other indices have been developed based on scoring systems.(6-8). These diagnostic scoring systems are useful in AIH research studies and may not substitute appropriate clinical assessment in routine patient evaluation.

Interpretation

Seropositivity for anti-liver/kidney microsomal antibodies type 1 antibodies is consistent with a diagnosis of autoimmune hepatitis type 2, in patients with compatible clinical symptoms and histopathology.

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.

Specimen Retention Time

14 days

Forms

If not ordering electronically, complete, print, and send 1 of the following with the specimen:

-Gastroenterology and Hepatology Test Request (T728)

-General Request (T239)

Testing Algorithm

For more information see First-Line Screening for Autoimmune Liver Disease Algorithm.