Abstract
Background: Rapid technological progress in point-of-care testing allows the measurement of multiple analytes in whole-blood samples. The present study evaluated biosensor-based methods for the measurement of electrolytes and substrates in whole blood using a Stat Profile Critical Care Xpress (Nova Biomedical, Waltham, MA, USA) multiprofile analyzer and their comparability with standard laboratory methods. Because of the increased utilization of arterial blood samples in hospitalized patients and limited information on differences between arterial and venous blood for most routine laboratory tests, analytical differences caused by different sample types were evaluated.
Methods: Whole-blood arterial samples and venous serum samples were obtained from 70 random patients with a variety of diagnoses admitted to the intensive care unit. The Stat Profile Critical Care Xpress analyzer was used to obtain whole-blood electrolyte and substrate profiles. For comparison studies, plasma or serum samples were analyzed according to standard laboratory methods using an Olympus AU 600 analyzer (Olympus Mishima, Shizuoka, Japan).
Results: Imprecision, expressed as the coefficient of variation (CV%), was less than 5.7% for all analytes at both high and low concentrations, except for creatinine, with a CV of 13.8% for low and 9.5% for high concentrations. The inaccuracy of electrolyte and substrate measurements in whole blood using a Stat Profile Critical Care Xpress analyzer met the analytical quality specification required for near patient testing, with observed bias within the range −4.5% to 5.3%. Statistically significant correlation (p<0.05) was obtained between standard laboratory methods performed on arterial plasma or venous serum samples on an Olympus AU 600 analyzer and direct whole-blood measurements on the Stat Profile Critical Care Xpress point-of-care analyzer for all parameters tested, although slope and intercept values showed analytical differences for electrolyte measurement.
Conclusions: The Stat Profile Critical Care Xpress multiprofile point-of-care analyzer provides rapid and accurate direct whole-blood measurement with acceptable performance compared to standard laboratory methods. The results obtained for electrolytes and substrates in whole blood were comparable to those for standard laboratory methods using arterial plasma or venous serum samples.
Clin Chem Lab Med 2006;44:898–903.
References
1. Kost GJ. New whole blood analyzers and their impact on cardiac and critical care. Crit Rev Clin Lab Sci 1993; 30:153–202.10.3109/10408369309084667Search in Google Scholar
2. Kost GJ, Vu H-T, Inn M, DuPlantier R, Fleisher M, Kroll MH, et al. Multicenter study of whole-blood creatinine, total carbon dioxide content, and chemistry profiling for laboratory and point-of-care testing in critical care in the United States. Crit Care Med 2000; 28,7:2379–89.10.1097/00003246-200007000-00033Search in Google Scholar
3. Fraser CG. Optimum analytical performance for point-of-care testing. Clin Chim Acta 2001; 307:37–43.10.1016/S0009-8981(01)00429-6Search in Google Scholar
4. Bullock DG. Quality control and quality assurance in point-of-care testing. In: Price CP, St John A, Hicks JM, editors. Point-of-care testing, 2nd ed. Washington, DC: AACC Press, 2004:137–45.Search in Google Scholar
5. Hyltoft Petersen P, Fraser CG, Kallner A, Kenny D. Strategies to set global analytical quality specifications in laboratory medicine. Scand J Clin Lab Invest 1999; 59:475–585.Search in Google Scholar
6. Nova Biomedical. Stat Profile® Critical Care Express. Instructions for user manual. Waltham, MA: Nova Biomedical, 2004:B5–7.Search in Google Scholar
7. ISO 9001:2000. Quality management system – requirements. Geneva: International Organization for Standardization, 2000.Search in Google Scholar
8. Passing H, Bablok W. A new biometrical procedure for testing the quality of measurement from two different analytical methods. Part I. J Clin Chem Clin Biochem 1983; 21:709–20.Search in Google Scholar
9. Ricoś C, Alvarez V, Cava F, García-Lario JV, Hernández A, Jiménez CV, et al. Biological variation database, 2001 update. www.westgard.com/guest17.htm.Search in Google Scholar
10. Briedigkeit L, Müller-Plathe O, Schlebusch H, Ziems J. Recommendations of the German Working Group Medical Laboratory Testing (AML) on the introduction and quality assurance of procedures for point-of-care testing (POCT) in hospitals. Clin Chem Lab Med 1999; 37:919–25.10.1515/CCLM.1999.136Search in Google Scholar
11. Kampa IS, Keffer P. The use of a whole-blood benchtop analyzer (Nova 16) in a cardiac stat intensive care unit. Clin Chem 1998; 44:884–5.10.1093/clinchem/44.4.884Search in Google Scholar
12. National Committee for Clinical Laboratory Standards. Method comparison and bias estimation using patient samples; approved guideline EP9-A. Wayne, PA: NCCLS, 1995.Search in Google Scholar
13. Burnett RW, Covington AK, Fogh-Andersen N, Külpmann WR, Levenstam A, Maas AH, et al. Recommendations for measurement of and conventions for reporting sodium and potassium by ion-selective electrodes in undiluted serum, plasma or whole blood. Clin Chem Lab Med 2000; 38:1065–71.10.1515/CCLM.2000.159Search in Google Scholar
14. Burnett RW, Covington AK, Fogh-Andersen N, Külpmann WR, Levenstam A, Maas AH, et al. Use of ion-selective electrodes for blood-electrolyte analysis. Recommendation for nomenclature, definitions and conventions. Clin Chem Lab Med 2000; 38:363–70.10.1515/CCLM.2000.052Search in Google Scholar
15. Lolekha PH, Vanavanan S, Teerakarnjana N, Chaichanajarernkul U. Reference ranges of electrolyte and anion gap on the Beckman E4A, Beckman Synchron CX5, Nova CRT, and Nova Stat Profile Ultra. Clin Chim Acta 2001; 307:87–93.10.1016/S0009-8981(01)00437-5Search in Google Scholar
16. Jagarinec N, Flegar-Meštrić Z, Šurina B, Vrhovski-Hebrang D, Preden-Kereković V. Pediatric reference intervals for 34 biochemical analytes in urban schoolchildren and adolescents. Clin Chem Lab Med 1998; 36:327–37.10.1515/CCLM.1998.055Search in Google Scholar PubMed
17. Sasse E, Bartell C, Durl M, Patsches M. Chemistry reference intervals for serum and plasma for the Beckman Synchron CX7 system utilizing the NCCLS C28-P guideline. Clin Chem 1995; 41:S199.Search in Google Scholar
18. Radiometer Medical. The blood gas handbook. Brønshøj: Radiometer Medical A/S, 2000.Search in Google Scholar
19. Steffes MW. Measurement of circulating glucose concentrations: the time is now for consistency among methods and types of samples. Clin Chem 2005; 51:1569–70.10.1373/clinchem.2004.044867Search in Google Scholar PubMed
20. Fogh-Anderson N, D'Orazio P. Proposal for standardizing direct-reading biosensors for blood glucose. Clin Chem 1998; 44:655–9.10.1093/clinchem/44.3.655Search in Google Scholar
21. D'Orazio P, Burnett RW, Fogh-Andersen N, Jacobs E, Kuwa K, Külpmann WR, et al. Approved IFCC recommendation on reporting results for blood glucose (abbreviated). Clin Chem 2005; 51:1573–6.10.1373/clinchem.2005.051979Search in Google Scholar PubMed
22. Sacks DB, Bruns DE, Goldstein DE, Maclaren NK, McDonald JM, Parrott M. Guidelines and recommendations for laboratory analysis in the diagnosis and management of diabetes mellitus. Clin Chem 2002; 48:436–72.10.1093/clinchem/48.3.436Search in Google Scholar
23. Doumas BT, Hause LL, Simuncak DM, Breitenfeld D. Differences between values for plasma and serum in tests performed in the Ektachem 700 XR analyzer, and evaluation of “plasma separator tube (PTS)”. Clin Chem 1989; 35:151–3.10.1093/clinchem/35.1.151Search in Google Scholar
24. Ciuti R, Rinaldi G. Serum and plasma compared for use in 19 common chemical tests performed in the Hitachi 737 analyzer [letter]. Clin Chem 1989; 35:1562–3.10.1093/clinchem/35.7.1562Search in Google Scholar
©2006 by Walter de Gruyter Berlin New York