Pregnancy-specific reference intervals for C-reactive protein improve diagnostic accuracy for infection: A...

Area of Science:

• Obstetrics and Gynecology
• Clinical Chemistry
• Infectious Diseases

Background:

• Infections pose a significant risk to maternal mortality.
• C-reactive protein (CRP) is a key inflammatory marker, but its normal range during pregnancy is unclear.
• Accurate interpretation of CRP requires pregnancy-specific reference intervals.

Purpose of the Study:

• To establish trimester-specific reference intervals for CRP in pregnant women.
• To evaluate the diagnostic accuracy of these new intervals for detecting intrauterine infections.
• To compare the diagnostic performance against existing CRP standards.

Main Methods:

• A longitudinal study of 322 healthy pregnant women was conducted to determine 95% reference intervals for CRP.
• A diagnostic accuracy study evaluated these intervals in 50 women with suspected intrauterine infection.
• CRP levels were analyzed in relation to gestational trimester and body mass index.

Main Results:

• CRP levels in pregnant women were substantially higher than in non-pregnant populations, with an upper limit of 19 mg/L across trimesters.
• CRP values showed a linear increase with body mass index (p < 0.0001).
• Using pregnancy-specific intervals, CRP demonstrated 73% sensitivity and 86% specificity for diagnosing chorioamnionitis, significantly improving overall accuracy (p = 0.03).

Conclusions:

• A pregnancy-specific reference interval for CRP is crucial for optimizing diagnostic accuracy in obstetric settings.
• The established intervals enhance the detection of localized infections like chorioamnionitis.
• These pregnancy-specific reference intervals for CRP should be adopted in all clinical scenarios involving pregnant women.