Table 1.

Characteristics of commonly used commercial assays for GH (according to manufacturers instructions/kit inserts available to the authors or according to published data). Calibration has changed for several assays in recent years, and the process is ongoing. To the best of the authors knowledge the assays listed here have uniformly adopted the latest recombinant standard for all countries. The list of assays is not complete. Additional hGH assays exist, including an unknown number of in-house assays. (modified from [3]

Manufacturer	Name	Assay principle	Calibration	Isoform-specificity	Measuring range	Recommended sample material	Comment
Siemens	Immulite 2000	Two-site Chemilumminescent immunometric assay	98/574	Not provided	0.05 to 40 ng/mL Analytical sensitivity: 0.01 ng/mL	Serum	ng/mL × 3.0 ➔mIU/L
Diasorin	Liaison hGH	Chemiluminescent sandwich immunoassay	98/574	Not provided	0.009–80 ng/mL	Serum
Beckmann-Coulter	Access Ultrasensitive hGH	Automated immunometric assay, Chemiluminescence	98/574	See comment	0.002–35 ng/mL (μ/L)	Serum or plasma (heparin)	Cross reaction analysed with GH 8 ng/mL for 20 K-GH: − 2542%
IDS	iSYS hGH	Chemilumminescent assay	98/574	22kD GH: 100%	0.05–100 ng/mL	Serum or plasma (heparin or EDTA)	Do not cross react with substances in these concentrations: 20 K-GH (10 ng/mL); placental GH (200 ng/mL); HPL (10,000 ng/mL); prolactin (40.000 ng/mL); pegvisomant (50,000 ng/mL); biotin 300 nmol/L); GHBP: 140 ng/mL. ng/mL × 3.0=μIU/mL
DIASource	hGH IRMA	Immunometric assay enzyme amplified sensitivity	98/574	Not provided	1–120 ng/mL Sensitivity: ng/mL	Serum, plasma	Conversion factor: 1μIU = 0.33 ng
	hGH EASIA	Enzyme-Immunoassay	98/574	Not provided	0.45–98 ng/mL Sensitivity:0.17 ng/mL	Serum, plasma	Conversion factor: 1μIU = 0.33 ng
CisBio	hGH-RIACT	Immunoradiometric	98/574	Not provided	0.03–75 ng/mL	Serum	1 ng = 3μIU; do not cross react with prolactin and hPL. Cross reaction with 20kD GH is less than 5% for the concentration up to 3750 ng/mL (22kD GH proportional concentration above 24,000 ng/mL)