Differences in Biomarker Concentrations in Serum and Urine of Patients with Ocular Tuberculosis – A Prospective Descriptive Study

PURPOSE:To describe biomarker concentrations in serum and urine of South African patients with ocular tuberculosis (OTB). METHODS:A prospective study to compare 29 urine and serum biomarkers in 14 OTB patients at a tertiary eye clinic. RESULTS:Median age of participants (7 male and 7 female) was 38.5 years (range 25-73) Most biomarker concentrations were significantly higher in serum than in urine (p < 0.01). Only 2 (IL-1RA and IL-2) showed higher concentrations in urine than serum (p < 0.01). Three biomarkers (sIL-2Ra, sTNFRI and IFNγ) showed no difference in concentration between urine and serum (p > 0.05). CONCLUSIONS:Most biomarkers tested showed significant differences in concentration between serum and urine and therefore these 2 biofluids cannot be used interchangeably when studying biomarker profiles. One notable exception is IFNγ as its concentration did not differ between serum and urine.