Testing leads to Type 1 autoimmune hepatitis diagnosis
Clinical cases: Gastroenterology
Situation
A 36-year-old woman presented with jaundice and dark urine. Initial labs showed ALT/AST-dominant elevation as well as elevated IgG. Viral-, drug-, and alcohol-related causes were not supported.
Results
ALDG2 test results:
- AMA-M2 IgG: <0.1 U: Negative
- HEp-2 IFA: Cytoplasmic fibrillar linear pattern detected
- SMA screen: Positive
- SMA titer: 1:160
Algorithm branch: SMA positive/HEp-2 IFA ±
Next steps
The HEp-2 IFA pattern from the ALDG2 test may guide add-ons and/or interpretation, including the FACT serum test.
- F-actin IgG: 86 U Positive FACT
Once a positive FACT test result is received, a biopsy should be performed. If the biopsy shows interface hepatitis, then the working interpretation would favor Type 1 autoimmune hepatitis (AIH).
Working interpretation: Type 1 AIH favored.
Teaching points
- The SMA-positive and HEp-2 IFA-positive with positivity for anti-F-actin IgG provide serologic support for Type 1 AIH, if compatible clinical features of disease are present. A diagnosis of AIH is favored.
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