Table 2.

Correlations between tandem MS and immunoassays

Steroid	Sy,x	Equations	n	Correlation coefficient (r)	Concentration ranges (ng/mL)
DHEASa	241.5	y = 1.15x + 43.18	50	0.971	14–3970
Cortisolb	17.98	y = 1.036x + 18.28	50	0.983	9.71–554
Androstenedionec	0.564	y = 1.051x + 0.769	50	0.905	0.1–6.8
Estriold,e	0.271	y = 1.132x + 0.079	13	0.959	0.8–3.3
Progesteronef	2.176	y = 1.236x − 0.502	50	0.988	0.215–52.8
DHEAc	1.26	y = 1.973x + 2.063	27	0.886	0.1–5.5
11-Deoxycortisolg	0.70	y = 0.668x + 1.711	9	0.888	1.0–6.0
Testosteroneg	0.633	y = 0.919x − 0.064	50	0.971	0.11–17.2
17-Hydroxyprogesteroneh	0.232	y = 1.587x + 0.123	46	0.988	0.11–6.07
Estradiola	1.392	y = 1.436x + 0.252	43	0.969	0.15–14.1

^aImmunoassay/DPC Immulite (Diagnostic Products Corporation).

^bImmunoassay/Bayer ADVIA Centaur.

^cRIA/Diagnostic Systems Laboratories, RIA indicates radioimmunoassay.

^dColorMetric/Bayer.

^eSamples of estriol were run in negative ion mode.

^fRIA/DPC Coat-A-Count.

^gRIA/ICN Pharmaceuticals.

^hExtracted RIA/Diagnostic Products Corporation.