Table 3.

Performance of Microbial Cell-Free DNA Test Versus Index Blood Culture

	True Positive	False Negative	False Positive	True Negative	Total	Sensitivity	Specificity
Index mcfDNA	116	21	9	26	172a	84.7%	74.3%/88.6%b
Any mcfDNA	125	15	13	22	175	89.3%	Not applicable

Sensitivity and specificity of either the index mcfDNA test or any mcfDNA obtained for each case vs the index blood culture. Listed by type of bacteremia with cumulative n = 172 in the index mcfDNA vs index blood culture analysis, n = 175 in the all mcfDNA vs index blood culture analysis.

^aExcludes 3 index samples that were QNS. Specificity based on 35 negative controls admitted but no suspicion of an infection.

^bSpecificity calculation based on the most common causes of bloodstream infection by the SENTRY Antimicrobial Surveillance Program.

Abbreviations: mcfDNA, microbial cell free DNA; QNS, quantity not sufficient.