OBJECTIVETo investigate the difference of serum high molecular weight alkaline phosphatase (HMAP) levels between biliary atresia (BA) and neonatal hepatitis (NH), and to develop a new differential method and early diagnostic indicators for cholestatic jaundice in neonates.

METHODSTotally 31 patients with cholestatic jaundice seen between Aug. 2000 and Feb. 2002, including 15 cases with BA, 16 cases with NH, 30 healthy infants and 30 infants with non-cholestatic jaundice were enrolled in this study. Serum samples were obtained from each subject by using venipuncture. The samples were stored at -80 degrees C and analyzed within 6 months. A murine hybridoma producing monoclonal antibody to human high molecular weight alkaline phosphatase (MoAb HMAP-1) was prepared by using partially purified HMAP from human serum as the immunogen. The antibody did not cross-react with other alkaline phosphatase (ALP) isozymes. A monoclonal antibody immunocatalytic assay for HMAP in serum was developed by using MoAb HMAP-1 bound to nitrocellulose membrane discs. The serum total ALP (TALP) and gamma-GT were determined in the meantime, the hepatobiliary ultrasonography and scintigraphy were performed too. The data were analyzed with t test, chi-square test and percentage. Comparisons were made between BA and NH with their sensitivity and specificity in different methods.

RESULTSSerum HMAP was detected in 14 of 15 patients of BA, in 2 of 16 NH patients, while in none of the healthy control group. The positive ratios of serum HMAP in BA and NH were 93.3% and 12.5%, respectively (P < 0.005). The sensitivity and specificity of serum HMAP in BA and NH were 93.3% and 87.5%, respectively. The sensitivity and specificity of TALP, gamma-GT and hepatobiliary scintigraphy were 80.0%, 73.3%, 86.7% and 62.5%, 68.8%, 62.5%, respectively, which were clearly lower than those of serum HMAP.

CONCLUSIONSThe determination of serum HMAP was more sensitive and specific than the other methods tested. Therefore the method can be used as a useful indicator for cholestatic jaundice in neonates, although it needs further study.

Alkaline Phosphatase ; blood ; Diagnosis, Differential ; Female ; Humans ; Immunoenzyme Techniques ; methods ; Infant ; Infant, Newborn ; Jaundice, Obstructive ; diagnosis ; Male ; Sensitivity and Specificity ; gamma-Glutamyltransferase ; blood