Table 2. Relative sensitivity, specificity, and likelihood ratios associated with serologic tests compared with RT-PCR test results in symptomatic patients by time period

Symptomatic patients, ≤ 7 days since first symptom
	RT-PCR (+)	RT-PCR (-)	Total	Sensitivity	4.9% (1.0% to 13.7%)
IgM or IgG (+)	3	5	8	Specificity	96.9% (92.9% to 99.0%)
IgM or IgG r (-)	58	157	215	LR+	1.59 (0.39 to 6.47)
Total	61	162	223	LR-	0.98 (0.92 to 1.05)
Symptomatic patients, 8 – 14 days
	RT-PCR (+)	RT-PCR (-)	Total	Sensitivity	27.3% (6.0% to 61.0%)
IgM or IgG (+)	3	2	5	Specificity	98.7% (95.4% to 99.8%)
IgM or IgG r (-)	8	154	162	LR+	21.27 (3.96 to 114.3)
Total	11	156	167	LR-	0.74 (0.51 to 1.06)
Symptomatic patients ≥ 15 days
	RT-PCR (+)	RT-PCR (-)	Total	Sensitivity	57.8% (44.8% to 70.1%)
IgM or IgG (+)	37	3	40	Specificity	98.4% (95.5% to 99.7%)
IgM or IgG r (-)	27	187	214	LR+	36.6 (11.69 to 114.71)
Total	64	190	254	LR-	0.43 (0.32 to 0.57)

RT-PCR = reverse transcriptase polymerase chain reaction; LR = likelihood ratio; IgM = immunoglobulin M; IgG = immunoglobulin G