Table 3.

Performance of TRF assay in detecting PA as PA83, PA63, and toxin complex in clinical samples. Results of testing 100 μl sera from ten confirmed clinical cases (cutaneous, inhalation, and gastrointestinal) and ten healthy persons. Concentration was determined using a PA83 standard curve.^a

Clinical Form	Time from Onset to Sera Collection (Days)	Lethal Factorb (ng/ml)	anti-PA IgGc (μg/ml)	TRF PA detection
				Concenetration (ng/ml)d	Coefficient of Variation (CV) (%)
Cutaneouse	8	0.996	<LLOQ	1.97	15.7
Cutaneouse	8	1.264	<LLOQ	1.02	14.8
Cutaneouse	7	0.310	<LLOQ	1.12	2.2
Cutaneouse	6	0.675	<LLOQ	1.70	17.3
Cutaneouse	1	<LOD	<LLOQ	4.03	5.3
Cutaneouse	3	1.105	<LLOQ	1.89	1.3
Cutaneouse	5	0.035	4.0	<LLOQ	NA
Inhalation	8	0.705	7.5	1.81	8.2
Inhalation	2	57.985	<LLOQ	68.73	2.2
Gastrointestinal	11	0.314	6.9	1.80	8.8
Healthy control	NA	NA	<LLOQ	<LLOQ	NA
Healthy control	NA	NA	<LLOQ	<LLOQ	NA
Healthy control	NA	NA	<LLOQ	<LLOQ	NA
Healthy control	NA	NA	<LLOQ	<LLOQ	NA
Healthy control	NA	NA	<LLOQ	<LLOQ	NA
Healthy control	NA	NA	<LLOQ	<LLOQ	NA
Healthy control	NA	NA	<LLOQ	<LLOQ	NA
Healthy control	NA	NA	<LLOQ	<LLOQ	NA
Healthy control	NA	NA	<LLOQ	<LLOQ	NA
Healthy control	NA	NA	<LLOQ	<LLOQ	NA

^aNA = not applicable

^bMeasured using mass spectrometry with a limit of detection (LOD) for lethal factor of <0.005 ng/ml (Boyer et al.,2007; Boyer et al., 2011a).

^cMeasured using ELISA with a lower limit of quantification (LLOQ) for anti-PA IgG of ≤3.7 μg/ml (Semenova, 2012).

^dThe limit of quantification (LOQ), based on the RDL, for PA is ≤0.551 ng/ml.

^eLethal factor and anti-PA IgG data from Boyer et al., 2011b.

^f 37.5 μl per well instead of 50 μl of sera was tested, result was divided by 0.75 to adjust for this volume difference.