A pregnancy-specific reference interval for procalcitonin

Abstract

Background and aims: Sepsis is a leading cause of maternal death, and developing diagnostic tests for infection is increasingly important to reduce maternal mortality. The existing inflammatory markers, like C-reactive protein, are not specific for infection, which introduces diagnostic uncertainty. Procalcitonin (PCT) is used to accurately diagnose bacterial sepsis and differentiate it from other conditions, which is now particularly important given the vulnerability to COVID-19 in pregnancy. There are few studies of PCT in pregnancy as the reference interval for pregnant women is unknown. This study aimed to define the pregnancy-specific reference interval for PCT.

Materials and methods: Cross-sectional study of 323 healthy pregnant women, with longitudinal sampling in each trimester.

Results: The upper reference limit for PCT was 0.05 ng/mL and did not vary materially between any observed group of gestational age, body mass index, maternal age, mean arterial blood pressure or fetal sex.

Conclusion: Our study has shown that levels of PCT are similar in pregnant and non-pregnant populations despite the physiological changes of normal pregnancy. Therefore, pregnancy should not preclude the use of PCT in pregnant women with suspected sepsis, or for guiding antibiotic therapy in women with a diagnosed bacterial infection at any stage of pregnancy.

Keywords: Infection; Pregnancy; Procalcitonin; Range; Reference interval; Sepsis.