Table 2.

Overview of cut-off ratios used for each marker per cohort comparison with corresponding sensitivity and specificity

Marker	Cohort comparison	AUC	Cut-off ratio	Sn/Sp
ApoA1	TB versus LTBI	0·57	>0 · 195	57%/66%
	COVID-19 versus healthy controls	0 · 85	<0 · 215	66%/90%
	COVID-19 versus TB	0 · 71	<0 · 285	96%/36%
CRP	TB versus LTBI	0 · 87	>0 · 585	77%/97%
	COVID-19 versus healthy controls	0 · 94	>0 · 990	93%/87%
	COVID-19 versus TB	0 · 93	>1 · 175	78%/96%
Ferritin	TB versus LTBI	0 · 66	>0 · 560	33%/97%
	COVID-19 versus healthy controls	0 · 96	>0 · 205	89%/92%
	COVID-19 versus TB	0 · 65	>0 · 405	71%/62%
IL-6	TB versus LTBI	0 · 76	>0 · 045	87%/59%
	COVID-19 versus healthy controls	0 · 72	>0 · 035	75%/67%
	COVID-19 versus TB	0·58	<0 · 045	34%/92%
IP-10	TB versus LTBI	0 · 70	>1 · 190	57%/79%
	COVID-19 versus healthy controls	0 · 82	>0 · 855	75%/74%
	COVID-19 versus TB	0·55	>1 · 260	41%/84%
SAA1/A2	TB versus LTBI	0 · 87	>0 · 345	100%/77%
	COVID-19 versus healthy controls	0 · 98	>0 · 900	92%/97%
	COVID-19 versus TB	0 · 92	>1 · 005	89%/82%
S100A12	TB versus LTBI	0 · 96	>0 · 045	88%/97%
	COVID-19 versus healthy controls	0 · 89	>0 · 125	70%/95%
	COVID-19 versus TB	0 · 79	>0 · 105	76%/70%

Overview of the cut-off ratios used per each individual marker in three different comparisons: TB vs. LTBI, COVID-19 versus healthy controls, and COVID-19 versus TB. The corresponding AUC, sensitivity and specificity are shown for each biomarker. A cut-off ratio for positivity for each biomarker was determined by calculating the maximal Youden’s index. Using the cut-offs for positivity, a NUM score was calculated; the number of biomarkers that scored above the threshold of positivity. AUCs in bold indicate the marker with the most discriminatory potential for a specific comparison; AUCs in italic font indicate a non-significant result. AUC: area under the curve; COVID-19: coronavirus disease 2019; LTBI: latent tuberculosis infection; Sn/Sp: sensitivity/specificity; TB: tuberculosis.