Aleksandra M Sowder1, Melanie L Yarbrough2, Robert D Nerenz2, John V Mitsios2, Rachel Mortensen3, Ann M Gronowski4, David G Grenache5. 1. Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA. 2. Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA. 3. ARUP Laboratories, Salt Lake City, UT, USA. 4. Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA; Department of Obstetrics and Gynecology, Washington University School of Medicine, St. Louis, MO, USA. 5. Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA; ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT, USA. Electronic address: david.grenache@path.utah.edu.
Abstract
BACKGROUND: The ability to perform quantitative hCG testing in whole blood at the point-of-care is desirable. The purpose of this study was to perform an analytical validation of the Abbott i-STAT Total β-hCG test. METHODS: Whole blood, plasma, and serum samples were prepared by the addition of hCG and were used to evaluate precision, linearity, analytical sensitivity, accuracy, the high-dose hook effect, and dilution recovery. RESULTS: Imprecision was highest with whole blood (CV = 16.0% and 6.7% at 10 and 1184 IU/l, respectively) and lowest in serum (CV = 8.1% and 4.3% at 11 and 1305 IU/l, respectively). The limits-of-quantitation were 8 and <5 IU/l for whole blood and both plasma and serum, respectively. The assay was linear between 5 and 2000 IU/l in all sample types (R(2) ≥ 0.998). i-STAT results agreed most closely with the Architect Total β-hCG assay and with greater differences observed with Beckman DxI Total βhCG and Roche Cobas e601 hCG+β assays (mean differences across all sample types were 9.3% and 12.3%, respectively). A high-dose hook effect was observed at concentrations > 400,000 IU/l. Accuracy was achieved in samples diluted with serum but not saline. CONCLUSIONS: The i-STAT Total β-hCG test demonstrates acceptable performance for quantifying hCG in whole blood, plasma and serum.
BACKGROUND: The ability to perform quantitative hCG testing in whole blood at the point-of-care is desirable. The purpose of this study was to perform an analytical validation of the Abbott i-STAT Total β-hCG test. METHODS: Whole blood, plasma, and serum samples were prepared by the addition of hCG and were used to evaluate precision, linearity, analytical sensitivity, accuracy, the high-dose hook effect, and dilution recovery. RESULTS: Imprecision was highest with whole blood (CV = 16.0% and 6.7% at 10 and 1184 IU/l, respectively) and lowest in serum (CV = 8.1% and 4.3% at 11 and 1305 IU/l, respectively). The limits-of-quantitation were 8 and <5 IU/l for whole blood and both plasma and serum, respectively. The assay was linear between 5 and 2000 IU/l in all sample types (R(2) ≥ 0.998). i-STAT results agreed most closely with the Architect Total β-hCG assay and with greater differences observed with Beckman DxI Total βhCG and Roche Cobas e601 hCG+β assays (mean differences across all sample types were 9.3% and 12.3%, respectively). A high-dose hook effect was observed at concentrations > 400,000 IU/l. Accuracy was achieved in samples diluted with serum but not saline. CONCLUSIONS: The i-STAT Total β-hCG test demonstrates acceptable performance for quantifying hCG in whole blood, plasma and serum.
Authors: Miranda M Brun; Laura Holloway; Amanda Oleksy; Jan Dayton; Mathew P Estey; Bobbi-Lynn Goudreau; Anna K Füzéry Journal: Pract Lab Med Date: 2019-01-11