Table 1.

Assay imprecision around the 4 µg/L screening cutoff for Immunalysis Sweat/Oral Fluid Δ⁹-THC Direct ELISA.

	Intraplate (n = 5), %		Interplate (n = 20), %		Interreada (n = 5), %
Control level (µg/L THC)	Mean (SD) B/B0b	CV	Mean B/B0	CV	Mean B/B0	CV
1	56.4 (1.6)	2.9	60.3 (1.8)	3.0	56.6 (0.3)	0.5
3	37.2 (2.9)	7.7	38.5 (2.0)	5.1	37.4 (0.3)	0.9
5	30.0 (1.1)	3.6	30.6 (2.8)	9.1	30.1 (0.2)	0.8
6	27.1 (2.0)	7.4	27.8 (1.3)	4.7	27.3 (0.2)	0.9

^aVariation in absorbance after addition of stop solution.

^bRaw absorbance values (B) normalized to the mean negative control absorbance value (B₀).