. 2015 Aug 1;35(6):573–582. doi: 10.1007/s10875-015-0184-y

Table 2.

Specificity and selectivity of the Ig-DBS assay

IgG
	Specificity		Selectivity
			IgG calibrator captured by anti-IgA			IgG calibrator captured by anti-IgM
	Matrix	IgG added at 3.1 ng/mL	37.5 ng/mL	18.75 ng/mL	9.38 ng/mL	37.5 ng/mL	18.75 ng/mL	9.38 ng/mL
Mean	<LLOQ	1.9	2.6^a	2.8^a	2.4^a	3.2^a	2.5^a	2.2^a
SD	–	0.2	–	–	–	–	–	–
% CV	–	8.9	–	–	–	–	–	–
% accuracy	–	62.3	–	–	–	–	–	–
^a<LLOQ of 4.7 ng/mL
IgM
	Specificity^a		Selectivity
			IgM calibrator captured by anti-IgA			IgM calibrator captured by anti-IgG
	Matrix	IgM added at 15.6 ng/mL	375.0 ng/mL	187.5 ng/mL	93.8 ng/mL	375.0 ng/mL	187.5 ng/mL	93.8 ng/mL
Mean	<LLOQ	<LLOQ	<LLOQ	<LLOQ	<LLOQ	<LLOQ	<LLOQ	<LLOQ
^bLLOQ = 46.9 ng/mL
IgA
	Specificity		Selectivity
			IgA calibrator captured by anti-IgG			IgA calibrator captured by anti-IgM
	Matrix	IgA added at 3.1 ng/mL	37.5 ng/mL	18.75 ng/mL	9.38 ng/mL	37.5 ng/mL	18.75 ng/mL	9.38 ng/mL
Mean	<LLOQ	2.8	1.1^a	1.1^a	1.1^a	4.2^a	2.5^a	1.8^a
SD	–	0.1	–	–	–	–	–	–
% CV	–	3.7	–	–	–	–	–	–
% accuracy	–	88.6	–	–	–	–	–	–
^a<LLOQ of 4.7 ng/mL

CV coefficient of variation, LLOQ lower limit of quantitation, SD standard deviation

^aThe assay was unable to quantify analyte added to matrix at 15.6 ng/mL as well as in matrix without added analyte, thereby demonstrating specificity

^bResults in the assay for all concentrations that are below the LLOQ of 46.9 ng/mL for the assay indicate no selectivity issue