Antibodies to liver/kidney microsome type-1 (anti-LKM-1) antigens occur in a subset of patients with autoimmune hepatitis (AIH), a chronic inflammatory condition of the liver. The clinical diagnosis of AIH is difficult because there are no particular signs, symptoms, or liver function test abnormalities that are specific enough to be considered diagnostic. Patients with AIH are predominantly children, but some patients are adults.
Different autoantibodies are found in the serum from patients with AIH. The discovery of the LKM-1 antibody led to the establishment of two subtypes of AIH. The percentage of patients with type 2 AIH whose serum contains LKM-1 antibodies is 90%. Patient sera are incubated on slides with mouse kidney and stomach. LKM-1 antibody produces a characteristic pattern, which allows it to be differentiated from the patterns produced by smooth muscle and mitochondrial antibodies on mouse tissue.
Negative: <20 U for LKM-1 by IFA
Equivocal: 20–25 U
Positive: >25 U
If positive, serum is titered.
Reference values are in arbitrary units and will vary with method of testing.
Collect a 7-mL blood serum sample in a red-topped tube. Observe standard precautions.
Label the specimen with the patient’s name, date, and test(s) ordered and place in a biohazard bag for transport to the laboratory.
Pretest Patient Care
Explain test purpose and procedure.
Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Care
Review test results; report and record findings. Modify the nursing care plan if needed. The primary therapy for AIH is administration of corticosteroids. Steroid treatment should lead to rapid reduction in aspartate transaminase and ALT (liver enzyme) levels.
Follow guidelines in Chapter 1 for safe, effective, informed posttest care.