Table 4. Diagnostic performance of soluble triggering receptor expressed on myeloid cells-1 (sTREM), midregional proatrial natriuretic peptide (proANP) and midregional proadenomedullin (proADM) biomarkers, as compared to white blood cell (WBC) count, neutrophils percentage, C reactive protein (CRP) and procalcitonin (PCT) at enrolment to predict severity of disease, according to biomarker cutoff with highest sensitivity and specificity.

Variable n	Biomarker cut-off value	Sensitivity	Specificity	PPV	NPV	AUC (95% CI)
Severe disease (n = 312)
sTREM-1, pg/mL 404	≥16.32	77.2%	38.6%	76.2%	40.0%	0.57 (0.51–0.64)
MR-proANP, pmol/L 407	≥33.8	70.9%	56.5%	80.5%	43.3%	0.65 (0.59–0.71)
MR-proADM, nmol/L 409	≥0.39	51.4%	66.1%	79.5%	34.7%	0.55 (0.49–0.61)
WBC count, cells/μL 428	≥13240	44.7%	71.4%	80.2%	33.2%	0.59 (0.53–0.65)
CRP, mg/L 426	≥1.04	77.2%	41.2%	77.2%	41.2%	0.58 (0.52–0.64)
Neutrophils % 413	≥55.4	69.9%	50.4%	78.1%	39.9%	0.59 (0.53–0.65)
PCT, ng/mL 265	≥0.093	76.8%	57.7%	83.2%	47.7%	0.65 (0.57–0.73)

AUC, area under the curve; 95% CI, 95% confidence interval; NPV, negative predictive value; PPV, positive predictive value.