Abstract Background Sepsis and its complications are one of the leading causes of mortality. Timely diagnosis and treatment are highly important in reducing morbidity and mortality. Serum biomarkers may aid in the early diagnosis of sepsis and therapeutic intervention. Procalcitonin (PCT) is a peptide precursor of the hormone calcitonin, and its primary trigger is infection. Increased serum PCT is associated with bacterial endotoxin and inflammatory cytokines. Therefore, PCT is widely used as a biomarker for bacterial infection and sepsis. Clinically, PCT greater than 2 ng/mL is associated with high risk of sepsis, and PCT less than 0.5 ng/mL is associated with low risk. We aimed to investigate the correlation between PCT and blood culture in the early diagnosis of sepsis in an unselected population with suspected bloodstream infections and evaluated the interpretative criteria helpful in diagnosis of systemic bacterial infection or sepsis. Methods We retrospectively analyzed medical records of 127 patients (72 (56.7%) males and 55 (43.3%) females) aged (X±SD(69.2±20.4) range (4-100 years) from different hospital departments who visited Dr. Sulaiman Alhabib Group of Hospitals (HMG) in Riyadh from January 2021 to December 2022. with suspected bloodstream infections who had PCT data and blood culture results. PCT was quantitatively determined by the BRAHMS PCT assay on the Abbott Allinity I System, which is a two-step chemiluminescent microparticle immunoassay (CMIA). Blood culture was done using BactAlert system (bioMérieux). Results Among study group blood culture was positive in 75 cases (59.1%) and negative in 52 cases (40.9), PCT was positive in 107 cases (84.3%) and negative in 20 cases (15.7%). Both tests were correlated (either positive or negative) in 71 cases (56%). PCT results were correlated to culture results (applying cutoff value 0.1 ng/ml) using Pearson Chi-Square test and results were insignificant (P value 0.5). PCT found to have sensitivity of 84% (73.7% to 91.5%, 95% CI) and specificity of 15.4% (6.9 to 28.1%, 95% CI) To assess the significance of interpretative criteria, PCT results were classified into 3 groups (moderate risk for progression to sever sepsis (0.5-1.99 ng/ml), sever systematic response (2-9.99 ng/ml) and high likelihood of sever sepsis or septic shock (= 10ng/ml). One way ANOVA studies show Significant difference among the 3 subgroups of culture negative cases (F value =3.48, P= 0.38) and among culture positive cases (F value= 4.56, P= 0.14). However, the student T test shows insignificant results when each risk category was compared among culture positive and negative cases (p value of 0.73, 0.83, 0.75 respectively). Conclusion PCT elevated levels in study population may indicate sepsis (good screening assay with accepted sensitivity) but should be interpreted cautiously alongside with blood culture results. Further research is needed to establish the specificity of PCT. Test interpretative criteria may work as good predictor of inflammatory status rather than septic status
Tamimi et al. (Wed,) studied this question.