Table 4.

Progesterone immunoassay cross-reactivity

Compound	Plasma/serum concentrations	Cross-reactivity in Roche assay	Likelihood of clinically significant cross-reactivity
Progesterone	• 0.2 – 1.4 ng/mL (males) [44]	100%	High (assay target)
	• Up to 27 ng/mL (women) [44]
5β-Dihydroprogesterone	Up to 0.8 ng/mL in adults [45]	18.2%	Possible significant contribution for individuals with progesterone concentrations on the lower end of reference interval
17-Hydroxyprogesterone	• 0.08 – 2.0 ng/mL (pediatric controls) [22]	1.2%	Low, except in patients with 21-hydroxylase deficiency
	• Up to 1,005 ng/mL (21-hydroxylase deficiency) [22]
Pregnanolone	Up to 17 ng/mL in women [33]	0.90%	Low
Allopregnanolone	Up to 29 ng/mL in women [33]	0.82%	Low
Medroxyprogesterone	Up to 100 ng/mL following dosing in women [46]	0.67%	Possible significant contribution for individuals with progesterone concentrations on the lower end of reference interval
Corticosterone	• 0.18 – 2.0 ng/mL (18 years and younger) [24]	0.54%	Low
	• 0.53 – 1.6 ng/mL (<18 years) [24]
11-Deoxycortisol	• 0.17 – 1.8 ng/mL (pediatric controls) [22]	0.39%	Low, except in patients following metyrapone challenge or who have 11β-hydroxylase deficiency
	• Up to 63 ng/mL (11β-hydroxylase deficiency) [22]
	• Up to 250 ng/mL (metyrapone challenge) [25]
Nandrolone	Up to 5.16 ng/mL in men following intramuscular injection [47]	0.17%	Low
Pregnenolone	Up to 3.27 ng/mL in women [33]	0.12%	Low
Exemestane	Up to 441 ng/mL in post-menopausal women [48]	0.09%	Possible significant effect if progesterone measured near peak of exemestane plasma concentration
Androstenedione	• Up to 0.86 ng/mL before onset of puberty [30]	0.09%	Low
	• Up to 3.2 ng/mL in 21-hydroxylase deficiency [30]