Plasma D-dimer reference ranges in pregnant Nigerians.

Background: The use of D-dimer as a screening test for thromboembolic disorders has not been validated in pregnancy thus necessitating further studies. This cross sectional study was carried out among Pregnant Nigerians at the Nigerian Air Force Hospital Antenatal Clinic, Ikeja, Lagos.

Objective: This study was to determine local reference ranges for plasma D-dimer in both pregnant and non-pregnant females and compare differences in both populations.

Methods: Structured questionnaires were administered on a total of 365 participants which included 71 apparently healthy non-pregnant females, 64 women in the first trimester of pregnancy (≤13 weeks gestation); 65 women at the second trimester of pregnancy (14-26 weeks), and 82 pregnant females at the third trimester of pregnancy (> = 27 weeks). Citrated blood was collected for estimation of prothrombin time (PT), activated partial thromboplastin time (aPTT), and D-dimer estimation by ELISA method. Aspartate aminotransferase (AST) and alanine aminotransferase enzymes (ALT) were estimated using the Hitachi chemistry analyzer. Reference ranges were estimated non-parametrically using the Reference Value Advisor V 2.1.

Results: Median D-dimer level for non-pregnant females was 190 ng/mL, while the median D-dimer levels for pregnant female in 1st, 2nd, and 3rd trimester were 485 ng/ml; 620 ng/mL; and 1185 ng/mL respectively.Reference ranges were calculated to be 86-494 ng/mL; 338-624 ng/mL; 451-799 ng/mL and 665-1262 ng/mL for non-pregnant females, 1st, 2nd, and 3rd trimester of pregnancy respectively.

Conclusion: A diagnostic algorithm for venous thromboembolism (VTE) in pregnant women which combines clinical suspicion with elevated plasma D-dimers levels above estimated reference range for each trimester should precede definitive formal imaging.