Plasma C-Reactive Protein and Pentraxin-3 Reference Intervals During Normal Pregnancy

Area of Science:

• Biochemistry
• Immunology
• Clinical Chemistry

Background:

• C-reactive protein (CRP) is a widely used biomarker for acute phase response.
• Long pentraxin 3 (PTX3), structurally related to CRP, is also implicated in inflammatory conditions and preeclampsia.
• Standard reference intervals for biomarkers may not be applicable during pregnancy due to physiological changes.

Purpose of the Study:

• To determine pregnancy-specific reference intervals for CRP and PTX3.
• To investigate the longitudinal changes of CRP and PTX3 levels throughout pregnancy.
• To assess the correlation between CRP, PTX3, and plasma albumin during gestation.

Main Methods:

• Longitudinal collection of plasma samples from 100 healthy pregnant women across three trimesters.
• Quantification of high-sensitivity CRP using turbidimetry.
• Measurement of PTX3 levels via enzyme-linked immunosorbent assay (ELISA).

Main Results:

• Both CRP and PTX3 levels showed similar trends, increasing significantly in the third trimester compared to the first and second trimesters.
• Third-trimester median CRP was 4.12 mg/L, and PTX3 was 7.70 µg/L.
• Plasma albumin was inversely correlated with CRP, but not with PTX3.

Conclusions:

• Pregnancy-specific reference values for CRP and PTX3 are essential for accurate interpretation.
• Elevated CRP and PTX3 levels in late pregnancy may occur in healthy individuals without infection.
• These findings highlight the need to adjust clinical interpretation of these biomarkers during pregnancy.