[Comparison of diagnostic utility between procalcitonin and C-reactive protein for the patients with blood culture-positive sepsis].
BACKGROUND
Procalcitonin (PCT) is a relatively new marker for bacterial infections, and its diagnostic utility has been variable across the studies. We investigated the diagnostic utility of PCT for the patients with blood culture-positive sepsis, and compared it with that of C-reactive protein (CRP).


METHODS
In 1,270 consecutive blood samples, PCT and CRP were simultaneously measured and results were compared according to the five categories of PCT concentrations (<0.05 ng/mL; 0.05-0.49 ng/mL; 0.5-1.99 ng/mL; 2-9.99 ng/mL; > or = 10 ng/mL). In 506 samples, they were further analyzed according to the result of blood culture. PCT and CRP were measured using enzyme-linked fluorescent assay (bioMerieux Co., France) and rate nephelometry (Beckman Coulter Co., USA), respectively. Their diagnostic utilities were compared using ROC curves.


RESULTS
The mean concentrations of CRP in five categories of PCT were 15.4 mg/L, 42.1 mg/L, 101.2 mg/L, 125.0 mg/L, 167.1 mg/L, respectively (P<0.0001). Both PCT and CRP showed significant differences between the two positive and negative groups of blood culture (PCT, 8.47 vs 2.44 ng/mL, P=0.0133; CRP, 110.48 vs 59.78 mg/L, P<0.0001). The areas under the ROC curves (95% confidence interval) for PCT and CRP were 0.720 (0.644-0.788) and 0.558 (0.478-0.636), respectively, and showed a significant difference (P=0.005).


CONCLUSIONS
The diagnostic utility of PCT is superior to that of CRP for the patients with blood culture-positive sepsis. PCT seems to be reliable for sepsis diagnosis, and may provide useful information for the critically ill patients.
Hur
Mina
M
Department of Laboratory Medicine, Konkuk University School of Medicine, Seoul, Korea. dearmina@hanmail.net
Moon
Hee-Won
HW
Yun
Yeo-Min
YM
Kim
Kyung Hee
KH
Kim
Hyun Soo
HS
Lee
Kyu Man
KM
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis*; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008875:Middle Aged; D009391:Nephelometry and Turbidimetry; D011498:Protein Precursors / Q000097:blood*; D012372:ROC Curve; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D018805:Sepsis / Q000175:diagnosis*
D015415:Biomarkers; C000606589:CALCA protein, human; D011498:Protein Precursors; D011933:Reagent Kits, Diagnostic; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide