Comparative Profile of HS-CRP, ESR, and Serum Protein Electrophoresis in Pelvic Inflammatory Disease, Rheumatoid Arthritis, and Pulmonary Tuberculosis

Abstract

High-sensitivity C-reactive protein (hs-CRP), erythrocyte sedimentation rate (ESR), and serum protein electrophoresis (SPEP) are widely available, low-cost inflammatory markers whose comparative behaviour across distinct inflammatory conditions is not well characterized in Nigeria. This cross-sectional study compared hs-CRP, ESR, and five SPEP fractions (albumin, α1-, α2-, β-, and γ-globulins) among 126 confirmed patients in Ilorin, Nigeria (42 each with pelvic inflammatory disease [PID], rheumatoid arthritis [RA], and pulmonary tuberculosis [PTB]), examining correlations among markers and with age, disease duration, and sex. All seven parameters differed significantly across groups (all p<0.0001); hs-CRP was highest in PID and lowest in RA, whereas ESR was highest in PTB and lowest in RA. PTB patients had the lowest albumin and highest α1- and α2-globulins (an acute-phase pattern), while RA patients had the most pronounced γ-globulin elevation despite modest hs-CRP and ESR. hs-CRP and ESR correlated strongly within each group (r=0.77–0.997, all p<0.0001) but only moderately when pooled (r=0.562), because the groups occupied distinct regions of the marker plane; the same pooled-versus-within-group divergence occurred for age and disease duration. At conventional cut-offs, hs-CRP and ESR were concordant (both elevated) in all 126 patients, with no discordant results. hs-CRP, ESR, and SPEP fractions show distinct, disease-specific profiles across PID, RA, and PTB, reflecting each condition's inflammatory kinetics, and inter-marker and demographic correlations depend heavily on whether disease group is accounted for. These findings support interpreting inflammatory-marker relationships within groups, rather than pooling them, in comparative studies of this kind.