OBJECTIVE: To assess the validity of Cystatin-C (Cys-C) and beta trace protein (BTP) as clinical markers of glomerular filtration rate (GFR) in pregnant women. DESIGN: Prospective cross sectional study. SETTING: Obstetric unit of a tertiary care hospital. POPULATION: One hundred and thirty-seven normal pregnant women and 13 women postpartum. METHODS: Twenty-four hour creatinine clearance (CrCl), serum creatinine, Cys-C and BTP concentrations were measured on normal pregnant women in the first trimester (n= 5), second trimester (n= 68) and third trimester (n= 64) and in 13 women postpartum. Data are given as median (2.5th centile, 97.5th centile). MAIN OUTCOME MEASURES: Serum concentrations of Cys-C and BTP compared with creatinine clearance and serum creatinine. RESULTS: The median serum creatinine throughout gestation was 53 micromol/L (39, 71), and median CrCl was 143 mL/minute (91 to 216). Postpartum, creatinine rose to 74 micromol/L (58, 86) and CrCl decreased to 104 mL/minute (71, 159). For Cys-C, the median concentration was 0.70 mg/L (0.46, 1.32), and 0.54 mg/L (0.36, 0.96) for BTP. Comparing the second and third trimesters, there was no significant difference between CrCl (median 145 vs 141 mL/minute) and BTP concentrations (median 0.51 vs 0.55 mg/L), while median Cys-C was significantly higher in the third trimester (0.61 vs 0.88 mg/L; P < 0.001). Unlike creatinine and BTP, Cys-C levels decreased to 0.72 mg/L (0.57, 0.95) postpartum. The only significant relationship of either of these markers to the standard used for GFR was between Cys-C and CrCl in the third trimester, and the correlation was weak (r= 0.27 for 1/Cys-C vs CrCl). CONCLUSION: These data demonstrate that despite claims to the contrary, Cys-C is a poor marker of GFR during pregnancy. Similarly, BTP shows little promise.
OBJECTIVE: To assess the validity of Cystatin-C (Cys-C) and beta trace protein (BTP) as clinical markers of glomerular filtration rate (GFR) in pregnant women. DESIGN: Prospective cross sectional study. SETTING: Obstetric unit of a tertiary care hospital. POPULATION: One hundred and thirty-seven normal pregnant women and 13 women postpartum. METHODS: Twenty-four hour creatinine clearance (CrCl), serum creatinine, Cys-C and BTP concentrations were measured on normal pregnant women in the first trimester (n= 5), second trimester (n= 68) and third trimester (n= 64) and in 13 women postpartum. Data are given as median (2.5th centile, 97.5th centile). MAIN OUTCOME MEASURES: Serum concentrations of Cys-C and BTP compared with creatinine clearance and serum creatinine. RESULTS: The median serum creatinine throughout gestation was 53 micromol/L (39, 71), and median CrCl was 143 mL/minute (91 to 216). Postpartum, creatinine rose to 74 micromol/L (58, 86) and CrCl decreased to 104 mL/minute (71, 159). For Cys-C, the median concentration was 0.70 mg/L (0.46, 1.32), and 0.54 mg/L (0.36, 0.96) for BTP. Comparing the second and third trimesters, there was no significant difference between CrCl (median 145 vs 141 mL/minute) and BTP concentrations (median 0.51 vs 0.55 mg/L), while median Cys-C was significantly higher in the third trimester (0.61 vs 0.88 mg/L; P < 0.001). Unlike creatinine and BTP, Cys-C levels decreased to 0.72 mg/L (0.57, 0.95) postpartum. The only significant relationship of either of these markers to the standard used for GFR was between Cys-C and CrCl in the third trimester, and the correlation was weak (r= 0.27 for 1/Cys-C vs CrCl). CONCLUSION: These data demonstrate that despite claims to the contrary, Cys-C is a poor marker of GFR during pregnancy. Similarly, BTP shows little promise.
Authors: A R Saxena; S Ananth Karumanchi; S-L Fan; G L Horowitz; N K Hollenberg; S W Graves; E W Seely Journal: Hypertens Pregnancy Date: 2011-10-18 Impact factor: 2.108
Authors: André Dallmann; Ibrahim Ince; Michaela Meyer; Stefan Willmann; Thomas Eissing; Georg Hempel Journal: Clin Pharmacokinet Date: 2017-11 Impact factor: 6.447
Authors: Sofia B Ahmed; Rhonda Bentley-Lewis; Norman K Hollenberg; Steven W Graves; Ellen W Seely Journal: Hypertens Pregnancy Date: 2009 Impact factor: 2.108