Assessment of biochemical and hematological profiles in outpatients with serological evidence of SARS-CoV-2 infection

Background SARS-CoV-2 infection is known to induce systemic biochemical and hematological alterations, particularly in hospitalized patients. However, data regarding subclinical changes in ambulatory, non-hospitalized individuals—especially in Latin American populations—remain limited. Objective To compare biochemical and hematological parameters between ambulatory adults with and without serological evidence of prior SARS-CoV-2 infection, in order to identify potential subclinical alterations associated with previous virus exposure. Methods A cross-sectional study was conducted in 201 ambulatory adults from central-northern Mexico between August and December 2020. Anti–SARS-CoV-2 IgG and IgM antibodies were detected using two independent lateral flow immunochromatographic assays. Participants were classified as seropositive only when both assays showed concordant reactivity. Biochemical and hematological parameters were compared between seropositive and seronegative individuals using appropriate parametric or non-parametric tests. Results Overall seroprevalence of anti–SARS-CoV-2 antibodies was 22.3%. No significant differences were observed in hematological parameters between seropositive and seronegative participants. In contrast, seropositive individuals exhibited significantly lower high-density lipoprotein cholesterol (HDL-C) levels compared to seronegatives (median: 40.5 vs. 45.3 mg/dL; p = 0.009), with significance maintained in females. Liver enzymes were significantly higher among seropositive subjects, including aspartate aminotransferase (AST) (median: 30 vs. 24 U/L; p = 0.007) and alanine aminotransferase (ALT) (median: 32.5 vs. 20 U/L; p = 0.001). These differences were more pronounced in males. No significant differences were found in glucose, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), alkaline phosphatase (ALP), or total bilirubin (TB). Conclusion Even mild or asymptomatic SARS-CoV-2 infection is associated with subtle but consistent alterations in lipid metabolism and liver enzymes in ambulatory, unvaccinated individuals. These findings support the need for biochemical monitoring after SARS-CoV-2 infection, particularly in populations with high baseline cardiometabolic risk.