Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (199 page)

   Diagnostic Criteria

   Definitive diagnosis requires all three criteria; probable diagnosis requires two criteria.

   Antimitochondrial autoantibodies present

   Cholestatic pattern (increased ALP) of long duration (>6 months) not due to known cause (e.g., drugs)

   Compatible histologic findings on liver biopsy

   Serum ALP is markedly increased; is of liver origin. Reaches a plateau early in the course and then fluctuates within 20% thereafter; changes in serum level have no prognostic value. 5′-N and GGT parallel the ALP.
This is one of the few conditions that will elevate both serum ALP and GGT to striking levels.

   Serum mitochondrial antibody titer is strongly positive in approximately 95% of patients (1:40–1:80) and is hallmark of disease (98% specificity); titer >1:160 is highly predictive of primary biliary cirrhosis (PBC), even in the absence of other findings. Does not correlate with severity or rate of progression. Titers differ greatly in patients. Similar titers occur in 5% of patients with chronic hepatitis; low titers occur in 10% of patients with other liver disease; rarely found in normal persons. Titer may decrease after liver transplantation but usually remains detectable.

   Serum bilirubin is normal in early phase but increases in 60% of patients with progression of disease and is a reliable prognostic indicator; an elevated level is a poor prognostic sign. Conjugated serum bilirubin is increased in 80% of patients; levels >5 mg/dL in only 20% of patients; levels >10 mg/dL in only 6% of patients. Unconjugated bilirubin is normal or slightly increased.

   Laboratory findings show relatively little evidence of parenchymal damage.

   AST and ALT may be normal or slightly increased (≤1–5 times normal), fluctuate within a narrow range, and have no prognostic significance.

   Serum albumin, globulin, and PT normal early; abnormal values indicate advanced disease and poor prognosis; not corrected by therapy.

   Marked increase in total cholesterol and phospholipids with normal triglycerides; serum is not lipemic; serum triglycerides become elevated in late stages. Associated with xanthomas and xanthelasmas. In early stages, LDL and VLDL are mildly elevated and HDL is markedly elevated (thus atherosclerosis is rare). In advanced stage, LDL is markedly elevated with decreased HDL and presence of lipoprotein-X (nonspecific abnormal lipoprotein seen in other cholestatic liver disease).