Potential pregnancy reference intervals determined

Recent research highlights substantial changes in blood biochemistry during pregnancy and establishes a trimester-specific reference database for 24 biochemical parameters (Clin Chem 2026;72:192-205).

Establishing trimester-specific reference intervals in healthy individuals poses challenges. Few studies focus on the degree to which maternal adaptation influences clinical marker concentrations, and research varies widely in analytical methodologies, measured biomarkers, and study design. To address this gap, researchers aimed to establish trimester-specific reference intervals for key biomarkers in a well-defined prospective cohort. They used a framework established by the Canadian Laboratory Initiative on Pediatric Reference Intervals.

The researchers collected blood samples at 0 and 13 weeks, 14–27 weeks, 28–42 weeks, and 1–3 months postpartum, then analyzed 24 biochemical parameters from 135 healthy pregnant individuals of median age 33.

Seventeen biomarkers had statistically significant changes. They included alkaline phosphatase, alanine transaminase (ALT), aspartate transaminase (AST), gamma-glutamyl transferase (GGT), creatinine, urea, uric acid, albumin, total protein, C-reactive protein, sodium, phosphate, cholesterol, triglycerides, high-density lipoprotein cholesterol, ferritin, and free thyroxine. Alkaline phosphatase demonstrated marked increases throughout gestation with statistically significant differences between the second and third trimesters and the early postpartum period. The derived upper reference limit for alkaline phosphatase doubled from the second to third trimester, decreasing proportionally in the early postpartum period. ALT, AST, and GGT had consistent reference value patterns throughout gestation but increased at 1–3 months postpartum, the researchers found.

Despite elevated liver enzymes in the postpartum period relative to earlier gestation, most reference values were below the recommended upper limit for nonpregnant adults, with flagging rates from 0–13%. Lactate dehydrogenase did not demonstrate statistically significant changes throughout gestation or the early postpartum period.

Creatinine, urea, and uric acid showed dynamic reference value patterns across gestation. Creatinine and urea demonstrated statistically significant decreases in all trimesters relative to the postpartum period. Upper reference limits derived for creatinine increased by 0.43 mg/dL between the second trimester and 1–3 months postpartum. Further, flagging rates for creatinine using a nonpregnant adult reference interval during pregnancy ranged from 33% in the first trimester to 63% in the third trimester, stabilizing at 8% in the early postpartum period.

Reference intervals were developed using only the Abbott Alinity ci-series system, so the researchers called for additional studies to apply findings to other analytical platforms.

Mexican biobank could help to advance personalized care

Data and findings from a Mexican biobank may aid treatment decisions in both Mexico and the United States, a recent study found (Nat Med 2026; doi.org/10.1038/s41591-025-04100-z).

Genetic testing for specific alleles often is recommended based on an individual’s ancestry. However, the frequency of pathogenic and pharmacogenomic alleles across different Hispanic groups has not been well-characterized, and existing guidelines often fail to recognize the geographic and ancestral diversity within these populations.

In response, researchers analyzed data from the Mexican Biobank, which includes genetic information from 40,000 individuals across 898 of Mexico’s urban and rural areas, including all 31 states and Mexico City. The researchers analyzed 6,011 of the samples with a commercially available genetic array to spot common variants known to affect drug response.

The researchers determined allele frequencies in each state in Mexico and found significant differences across populations and states. For example, nearly 40% of the Chiapas population carries two copies of the allele rs2242480, which is linked to slower fentanyl metabolism. In contrast, in the northern state of Sinaloa, only 10% of people do. People with origins in Chiapas, Oaxaca, and Yucatán might benefit from pharmacologic testing for different reasons depending on where they live, the researchers suggested.

The variant SLCO1B1, known to hinder statin metabolism, was found in less than 1% of Mexicans from northern states, but in more than 15% of people from the Yucatán Peninsula. Based on these findings, the researchers also suggested that national guidelines should consider adjusting statin dosing in these populations based on genetic testing to reduce the risk of myopathy and rhabdomyolysis associated with long-term exposure.

The researchers plan to make results available for 42,769 biomedically relevant genotyped variants through MexVar, a user-friendly platform designed to improve access to genomic data for the scientific community and to support genetic analyses for populations of Mexican descent worldwide.

Sample self-collection equally good for HPV and STI screening in an underserved population

Equal proportions of women from marginalized backgrounds — nearly 1 in 6 — tested positive for human papillomavirus (HPV) and another of three sexually transmitted infections (STIs) in a recent study of sample self-collection in this population (JAMA Netw Open 2026; doi:10.1001/jamanetworkopen.2025.51345).

HPV sample self-collection increases cervical cancer screening uptake among underscreened women from marginalized low-income and racial and ethnic backgrounds, previous research shows.

To address this issue, the researchers conducted a secondary analysis of the My Body, My Test–3 study, a randomized clinical trial testing a mailed self-collection intervention to improve cervical cancer screening. In the secondary study, the researchers aimed to evaluate an intervention featuring streamlined testing for chlamydia, gonorrhea, and trichomoniasis, alongside HPV self-collected samples. Using mailed self-collection kits, they determined the prevalence of HPV and the other STIs with simultaneous testing of a population of low-income women in 22 counties in North Carolina, who were overdue for cervical cancer screening. The study randomized the 327 women to the trial intervention group with valid STI and HPV results. The researchers tested samples using the Aptima assay.

Among participants of median age 42, of which 8.6% were Hispanic, 44.7% were non-Hispanic Black, and 133 were non-Hispanic White. Nearly 1 in 6 participants, or 15.6%, tested positive for one of the other STIs, the same rate as those positive for HPV. Just over 2% tested positive for both. Risk factors for other STIs included non-Hispanic Black race and ethnicity, White race and ethnicity, having two or more sexual partners in the last year compared with having none, being single compared to being partnered, and smoking.

Among participants who tested positive for other STIs, 66.7% received follow-up care, the researchers reported.

Read the full March-April 2026 issue of CLN.