Gestation-specific reference intervals for renal and liver function tests and complete blood count in a Chinese cohort: a retrospective cross-sectional study

Abstract

Reference intervals for renal and liver function tests and complete blood count are influenced by gestational age, ethnicity, and analytical methods. Establishing pregnancy-specific reference intervals is essential for accurate diagnosis and management of obstetric conditions. This study aimed to define gestation-stratified reference intervals for 29 biochemical and hematological parameters in a Chinese population. In this cross-sectional study, 23,514 pregnant Chinese women (aged 18–35 years) underwent prenatal check-ups across trimesters were initially enrolled. After applying exclusion criteria, laboratory data from remaining participants were retained for Reference interval establishment. Gestation-stratified RIs were established in strict accordance with CLSI EP28-A3c and WS/T 402–2024 guidelines, computing trimester-specific Reference intervals. Subsequently, decision tree modeling automated gestational age subgrouping by identifying inflection points in cross-sectional trends across gestation, enabling data-driven Reference interval construction for optimized physiological intervals. Furthermore, continuous gestational age-dependent Reference intervals were derived via the Lambda-Mu-Sigma method. Key quantitative findings included a more than two-fold increase in the upper reference limit for alkaline phosphatase by the third trimester (from 74.00 to 275.57 U/L), moderate elevations in aspartate aminotransferase, lactate dehydrogenase, and total bile acids, and progressive declines in alanine aminotransferase, albumin, and cholinesterase. Hemodilution was evident from a decline in hemoglobin (lower reference limit decreased to 98 g/L) and platelet count (lower reference limit decreased to 98 × 10⁹/L) in late pregnancy, while the white blood cell count upper reference limit rose to 14.99 × 10⁹/L. Renal function adaptations were marked by a late-pregnancy surge in uric acid (upper reference limit : 458.00 µmol/L) and cystatin C (upper reference limit: 1.54 mg/L). Pregnancy-specific reference intervals mitigate misinterpretations of hepatic, renal, and hematological parameters. Using standardized methodologies, we established trimester-stratified Reference intervals for healthy pregnancies and gestational age-specific percentile curves, enhancing evidence-based clinical precision. Conventional gestational reference intervals fail to accurately capture the dynamic physiological adaptations of pregnancy. This study is the first to establish gestation-specific reference intervals for liver and kidney function tests and complete blood count in a Chinese population. Through the novel application of decision tree modeling and the Lambda-Mu-Sigma method to generate continuous reference intervals, it provides an essential evidence base for precise obstetric diagnosis and clinical management.

The authors' abstract, as published at the source. BMC Pregnancy and Childbirth, 2026 · DOI ↗