Table 4.

Reference values, with their associated uncertainties, and indicative values (without uncertainty) for serum testosterone standardisation. Reference and Indicative values supplied by NMIA for testosterone in the CC and the Unknown human sera samples were applied as the agreed “true” values for the CC, RCPAQAP and Unknown samples.

Sample	Values provided by company (with associated uncertaintya)			Values provided by NMIA (with associated uncertainty a,b)
	Expected ng/mL	Measured ng/mL	Expected nmol/Lc	Mass fraction ng/g	Molar Concentration nmol/L
RCPAQAP Level 1	N/A			0.228 ± 0.021	0.804 ± 0.072 (9.0%)
RCPAQAP Level 2				1.206 ± 0.055	4.27 ± 0.19 (4.6%)
RCPAQAP Level 3				2.33 ± 0.11	8.27 ± 0.40 (4.9%)
RCPAQAP Level 4				3.35 ± 0.18	11.89 ± 0.65 (5.4%)
RCPAQAP Level 5				4.34 ± 0.18	15.45 ± 0.65 (4.2%)
RCPAQAP Level 6				5.38 ± 0.18	19.16 ± 0.63 (3.3%)
Common Calibrator 1	0.01	0.011 ± 0.002	0.035	0.009	0.033
Common Calibrator 2	0.04	0.038 ± 0.003	0.139	0.035	0.123
Common Calibrator 3	0.20	0.20 ± 0.02	0.693	0.190	0.676
Common Calibrator 4	0.8	0.80 ± 0.03	2.77	0.738	2.609
Common Calibrator 5	3.0	3.0 ± 0.2	10.4	2.86	10.16
Common Calibrator 6	6.0	6.0 ± 0.2	20.8	5.61	20.00
Common Calibrator 7	10.0	10.0 ± 0.4	34.7	9.38	32.21
Unknown 1 (adult male)	N/A			4.67	15.98
Unknown 2 (adult female)				0.163	0.570

^aNote: Measurement uncertainties are expanded uncertainties determined at a level of confidence of 95%.

^bThe density of the Common Calibrator is 1.006.

^cThe average molecular weight of testosterone is 288.424 Da was used to convert the expected value from ng/mL to nmol/L (ChemSpider ID 5791 - http://www.chemspider.com/)