. 2006 Sep 13;13(11):1197–1203. doi: 10.1128/CVI.00174-06

TABLE 4.

Summary of influences of specimen preparation and method of analysis on measurement of substance P in paired rhesus macaque and human plasmas; comparison of standard curve definitions (in human plasma)

Assay	n	Substance SP level (pg/ml) (mean ± SD)			95% CI of LOA and bias^a
Assay	n	Recommended	User-modified	Mean difference	95% CI of LOA and bias^a
Cayman EIA	5	58.6 ± 3.1	67.0 ± 5.7	−8.4 ± 6.2	Bias^b (−16.1, −0.7)
					LOA^c (−20.5, 3.7)
					Lower LOA^d (−33.8, −7.2)
					Upper LOA^d (−9.6, 17.0)
Assay Designs EIA	5	183.2 ± 51.2	28.4 ± 5.8	−154.9 ± 51.5	Bias (−218.8, −91.0)
					LOA (−255.8, −54.0)
					Lower LOA (−366.6, −145.1)
					Upper LOA (−164.7, 56.8)

Bland and Altman (2, 3) 95% confidence intervals for LOA and bias.

95% CI bias = mean difference ± t critical value on n − 1 degrees of freedom × standard error of mean difference (SE).

95% CI LOA = mean difference ± 1.96 × SD.

95% CI lower LOA = (mean difference − 1.96 × SD) ± t critical value on n − 1 degrees of freedom × 1.732 × SE; 95% CI upper LOA = (mean difference + 1.96 × SD) ± t critical value on n − 1 degrees of freedom × 1.732 × SE.