The purpose of this study was to determine serum alpha(2)-HS glycoprotein (AHSG) concentration and its diagnostic accuracy in preeclampsia. In this case-control study, the serum C-reactive protein (CRP) and AHSG levels were measured in 93 preeclamptic patients and in 127 healthy pregnant women by immunoturbidimetry and radial immunodiffusion. The serum CRP levels were significantly higher, whereas the serum AHSG concentrations were significantly lower in the preeclamptic group than in the control group (median (25th to 75th percentile), CRP: 6.71 mg l(-1) (2.76-12.69) vs. 3.38 mg l(-1) (1.69-7.27), respectively; AHSG: 660 microg ml(-1) (612-768) vs. 744 microg ml(-1) (660-816), respectively; P<0.001 for both). In preeclamptic patients, the serum AHSG concentrations showed significant inverse correlations with systolic blood pressure and serum CRP levels. A low serum AHSG level (< or = 720 microg ml(-1)) was significantly associated with preeclampsia (adjusted odds ratio (95% confidence interval): 3.69 (1.82-7.51); P<0.001). According to the receiver operating characteristic curves, the measurement of serum AHSG concentrations was as accurate as that of serum CRP levels to detect preeclampsia. In conclusion, serum AHSG concentration is decreased and reflects-at least partly-systemic inflammation in preeclampsia.