Interleukin-6 measured using the automated electrochemiluminescence immunoassay method for the identification of intra-amniotic inflammation in preterm prelabor rupture of membranes

Abstract

Introduction: We aimed to compare the amniotic fluid interleukin (IL)-6 concentrations measured using the automated electrochemiluminescence immunoassay method and ELISA, and to establish an IL-6 concentration cut-off value for intra-amniotic inflammation (IAI) in preterm prelabor rupture of membranes (PPROM), which can be used in the automated electrochemiluminescence immunoassay method.

Materials and methods: A total of 120 women with PPROM were included in this study. Amniotic fluid samples were obtained through transabdominal amniocentesis. IL-6 concentrations were assessed using both the automated electrochemiluminescence immunoassay method and ELISA, the current gold standard. IAI was defined as an amniotic fluid IL-6 concentration of ≥2600 pg/mL measured using ELISA.

Results: A correlation between both assays was found (Spearman’s rho = 0.97; p < .0001). Based on the receiver-operating characteristic curve for the identification of IAI (area under the curve = 0.99), a cut-off value of ≥3000 pg/mL was selected for the automated electrochemiluminescence immunoassay method with a sensitivity of 88%, specificity of 99%, positive predictive value of 97%, negative predictive value of 96%, and likelihood ratio of 76.

Conclusions: For amniotic fluid IL-6 concentrations assessed using the automated electrochemiluminescence immunoassay method, a cut-off value of 3000 pg/mL was indicated for diagnosing IAI in women with PPROM.

Keywords:

• Amniotic fluid
• cytokine
• immunoassay method
• marker
• preterm birth

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Faculty Hospital in Hradec Králové (long-term organization development plan). Additional support was obtained from Charles University, Prague; Faculty of Medicine in Hradec Králové, Czech Republic; and project “PROGRES Q40”.