Reference values for α1-acid glycoprotein, α1-antitrypsin, albumin, haptoglobin, C-reactive protein, IgA, IgG and IgM during pregnancy

The objective of this study was to establish reference intervals and decision limits for the interpretation of the acute phase proteins α1‐acid glycoprotein (orosomucoid), α1‐antitrypsin, C‐reactive protein (CRP), haptoglobin and albumin, IgA, IgG and IgM during pregnancy by longitudinal sampling from 52 healthy women with normal pregnancies. Each woman was sampled in weeks 7–17; weeks 17–24; weeks 24–28; weeks 28–31; weeks 31–34; weeks 34–38 and predelivery (–14–0 days prior to delivery) and postpartum (>6 weeks after delivery). The 2.5th and 97.5th percentiles were calculated according to the recommendations of the International Federation of Clinical Chemistry on the statistical treatment of reference values. Reference values for α1‐acid glycoprotein, α1‐antitrypsin, albumin, haptoglobin, CRP, IgA, IgG and IgM are reported. Most of these proteins changed during normal pregnancy, as a reflection of the major physiological and biochemical changes that occur in pregnancy. A laboratory test result from a pregnant woman should be compared with pregnancy‐specific reference intervals.