Analytical and clinical validation of the Immulite 1000 hCG assay for quantitative analysis in urine

Background: The Siemens Immulite hCG assay detects all major hCG variants in serum. Currently, this assay is only FDA approved for qualitative measurement of hCG in urine. Methods: Complete validation of the hCG assay in urine was performed on the Siemens Immulite 1000 immunoassay platform. Reference intervals were established for females <55 y, females >= 55 y, and males 20-70 y. Results: The limit of quantitation was 2.0 IU/l. The Immulite hCG assay was precise for measuring hCG in urine from pregnant patients with intra- and inter-assay imprecision of <11% CV. The assay was linear over a dynamic range of 2-2600 IU/l and 2-3500 IU/l for hCG and hCG beta respectively. The assay was non-linear for hCG beta cf. No hook effect was observed at concentrations up to 1,200,000 pmol/l for hCG beta or hCG beta cf. The reference intervals were <2.0 IU/l for males, <2.2 IU/l for females <55 y, and <12.2 IU/l for females >= 55 y. Conclusion: The Immulite 1000 hCG assay can accurately quantify hCG in urine. (C) 2013 Published by Elsevier B.V.