Table 5 Testosterone immunoassay 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]