Development of an enzyme-linked immunosorbent assay for 2,3-dinor-6-keto-prostaglandin F1 alpha in urine using a monoclonal antibody.

OBJECTIVES: To develop and validate an enzyme-linked immunosorbent assay (ELISA) for measurement of urinary 2,3-dinor-6-keto-prostaglandin F1 alpha (2,3D6KPGF1 alpha) using a monoclonal antibody and a horseradish peroxidase-linked antigen. DESIGN AND METHODS: Assay validation included optimization of the standard curve, antibody cross-reactivity, accuracy and imprecision studies together with preliminary measurement of clinical samples. RESULTS: Optimal conditions of the standard curve (0.078-10.0 micrograms/L) used 2 mg/L of antibody and 3 micrograms/L of peroxidase conjugate in each well, at pH 7.2. The coefficient of variation of various concentrations of the standard curve averaged 6.8%. Antibody cross-reactivity was < 0.01% for related prostanoids. Recovery of known amounts (0.1-5.0 micrograms/L) of 2,3D6KPGF1 alpha added to an urinary sample was 101.2 +/- 6.3%. Imprecision studies with non-pregnant (0.24 microgram/L) and pregnant (2.5 micrograms/L) samples displayed an intraassay variability of 8.9 and 9.9%, and an interassay variability of 9.6 and 10.0%, respectively. Urinary measurements in the non-pregnant and pregnant states were similar to those previously reported. An apparent decreased concentration was observed early in pregnancy in future preeclampsia. CONCLUSION: With similar precision and validity, our assay method is time- and cost-saving. Preliminary urinary measurements show that this analyte may be of interest as an early marker for preeclampsia.