Serum sFlt-1/PlGF ratio has better diagnostic ability in early- compared to late-onset pre-eclampsia.

Background To establish gestational specific cutoffs for the soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) ratio as a diagnostic tool for pre-eclampsia (PE) in an Asian population. Methods 82 subjects (48 PE patients and 34 controls) were recruited. sFlt-1 and PlGF were analysed on the Roche Cobas e411 analyzer and their ratio was calculated. Diagnostic performance was evaluated using receiver-operating characteristics (ROC) curves. Optimal cutoffs for sFlt-1/PlGF ratio were determined for different gestation phases. Results The most optimal cut-off for the study group is 32 with a sensitivity and specificity of 85.1% and 100% and Youden Index (J) of 0.85. Applying this cutoff for early-onset PE (EO-PE), sensitivity increased to 95.8% while specificity remains at 100% (J=0.96). However, for late onset PE (LO-PE), sensitivity decreases to 73.9% while specificity remains at 100% (J=0.74). Two cutoffs were further determined for EO-PE and LO-PE - the first focusing on high sensitivity; the second focusing on high specificity. For EO-PE, cutoff <17 yielded sensitivity of 100% and specificity of 94.4% (J=0.94) while cutoff ≥32 yielded sensitivity of 95.8% and specificity of 100% (J=0.95). For LO-PE, cutoff <22 has a sensitivity of 82.6% and a specificity of 91.7% (J=0.74) while cutoff ≥32 yielded sensitivity of 73.9% and specificity of 100% (J=0.74). Conclusion While our study found an overall cutoff at 32 regardless of gestation age, it has limited diagnostic accuracy for LO-PE in our study. Multiple cutoffs focusing on either high sensitivity or high specificity enhance the performance of the sFlt-1/PlGF ratio as a diagnostic tool for PE and contribute to the identification of women at risk of PE in our Asian region.

Gestational age-specific reference intervals for serum thyroid hormone levels in a multi-ethnic population.

BACKGROUND: Thyroid disorders are common during pregnancy. To date, a limited number of studies have reported differences in serum thyroid hormone concentrations between different ethnic groups. We sought to establish gestational age-specific reference intervals for serum levels of thyroid hormones in a multi-ethnic population and investigate whether separate reference intervals should be used for different ethnic groups. METHODS: A total of 926 pregnant women from multiple ethnic groups attended four separate study visits spanning the three trimesters. Venous blood samples were taken at 9 to 14 weeks, 18 to 22 weeks, 28 to 32 weeks, and 34 to 39 weeks of gestation. Serum concentrations of thyroid-stimulating hormone (TSH), free thyroxine (T4), free triiodothyronine (T3), total T4, total T3, thyroid peroxidase antibody and thyroglobulin antibody were measured using Abbott Architect immunoassays. A total of 562 women with singleton pregnancies were found to be negative for both thyroid autoantibodies at all four study visits and thus included in the reference sample group for the establishment of reference intervals (2.5th to 97.5th percentiles). RESULTS: Reference intervals for serum thyroid hormones at 9-14 weeks of gestation derived from the combined group of pregnant women are as follows: TSH, 0.01-2.39 mIU/L; free T4, 11.4-19.5 pmol/L; free T3, 4.23-6.69 pmol/L; total T4, 77.8-182.4 nmol/L; total T3, 1.39-2.97 nmol/L. No differences in the five thyroid parameters' reference intervals are detectable among the ethnic groups except that at study visit 3 (28-32 weeks of gestation), the upper reference limit of total T3 in Malays (3.20 nmol/L; 90% CI, 2.99-3.76 nmol/L) is slightly higher than that in Chinese (2.86 nmol/L; 90% CI, 2.70-2.98 nmol/L). CONCLUSIONS: The findings from this study on a multi-ethnic cohort highlight the importance of establishing locally derived and gestational age-specific reference intervals for the five thyroid hormone parameters.