Table 5.

Testosterone immunoassay cross-reactivity

Compound	Plasma/serum concentrations	Cross-reactivity in Roche assay	Likelihood of clinically significant cross-reactivity
Testosterone (endogenous compound)	• 0 – 10 ng/mL (males) [49]	100%	High (assay target)
	• 0 – 0.5 ng/mL (females) [49]
Methyltestosterone	Up to 40 ng/mL following single dose [50]	12.2%	High, especially if measured during peak concentration
Boldenone	Up to 1.1 ng/mL in horses following dosing [51]	7.2%	Likely low, although there is lack of human pharmacokinetic data
19-Norclostebol	Unknown	6.7%	Unknown, no human pharmacokinetic data available
Norethindrone	Up to 20 ng/mL while on medication [39-41]	6.7%	Possible significant contribution in women taking norethindrone, especially if specimen drawn near peak of norethindrone concentration
11β-Hydroxytestosterone	Unknown	5.5%	Unknown, no human pharmacokinetic data available
Methandrostenolone	Unknown	5.4%	Unknown, no human pharmacokinetic data available
Normethandrolone	Unknown	5.4%	Unknown, no human pharmacokinetic data available
Nandrolone	Up to 5.16 ng/mL [47]	2.1%	Low
Androstenedione	• Up to 0.86 ng/mL before onset of puberty [30]	1.2%	Low
	• Up to 3.2 ng/mL in 21-hydroxylase deficiency [30]