Table 1. Demographic information for the enrolled cohort as well as independent data sets used for external validation.

M, male; F, female; B, black; W, white; O, other/unknown. GSE numbers refer to National Center for Biotechnology Information (NCBI) Gene Expression Omnibus data sets. N/A, not available on the basis of published data.

CohortNo. of
Mean age,
years (range)
AdmittedNo. of samples
(viral/bacterial/noninfectious illness)
Enrolled derivation cohort317122/15145 (6–88)135/116/2261%115/70/88
  Viral11544/7145 (6–88)40/59/1621%
  Bacterial7035/3549 (14–88)46/22/294%
  Noninfectious illness8843/4549 (14–88)49/35/488%
  Healthy4423/2130 (20–59)8/27/6§0%
Validation cohorts
  Ramilo et al. (GSE6269)11362/514 (0.04–36)22/37/54100%28/85/0
  Hu et al. (GSE40396)4325/1814 (2–32)16/25/2N/A35/8/0
  Herberg et al. (GSE42026)59N/APediatricN/A100%18/41/0
  Parnell et al. (GSE20346)||104/6AdultN/A100%19/26/0
  Bloom et al. (GSE42834)103N/AAdultN/AN/A0/19/84

*Only subjects with viral, bacterial, or noninfectious illness were included (when available) from each validation cohort.

†When mean age was unavailable or could not be calculated, data are presented as either adult or pediatric.

‡Noninfectious illness was defined by the presence of systemic inflammatory response syndrome (SIRS) criteria, which include at least two of the following four features: temperature <36° or >38°C; heart rate >90 beats per minute; respiratory rate >20 breaths per minute or arterial partial pressure of CO2 <32 mmHg; and white blood cell count <4000 or >12,000 cells/mm3 or >10% band form neutrophils.

§Three subjects did not report ethnicity.

¶In the case of GSE6269, subjects with Illumina Sentrix Hu6 expression data were excluded because array results could not be readily compared. Eight viral and 15 bacterial infections comprised the 24 excluded cases.

||Subjects in the GSE20346 data set include serial sampling. The number of samples exceeds the number of subjects because serial samples were treated as independent tests in the validation experiments.