Elecsys® total prostate specific antigen (total PSA) Electro-chemiluminescence immunoassay (ECLIA) for the quantitative determination of total PSA in human serum and plasma 1 Indication Prostate-specific antigen (PSA) is a glycoprotein (molecular weight of approximately 34 kD) having a structural relationship to the glandular kallikreins. It has the function of a serine proteinase and its main role is to liquify semen and to dissolve the c ervical mucous cap, allowing the entry of sperm. The proteolytic activity of PSA in blood is inhibited by the irreversible formation of complexes with protease inhibitors such as alpha-1-anti-chymotrypsin (ACT) and others. Approximately 30 % of the PSA present in blood occurs in the free form, but is proteolytically inactive.2 Measurement of total PSA is clinically useful in the following way: •Elevated concentrations of PSA in serum are generally indicative of a pathologic condition of the prostate like prostatitis, benign prostate hyperplasia (BPH) or carcinoma.3 By combining PSA determination and digital rectal examination (DRE) the detection rate of prostate cancer can be increased. •Although ACT is present in excess in human serum, a high percentage of free PSA (approximately 30 %) can be found in patients with BPH. Determination of the free/total PSA ratio increases the specificity of PSA. •Monitoring of progress and efficiency of therapy in patients with prostate carcinoma4 whereby the steepness of the rate of fall in PSA down to undetectable levels after adequate treatment provides information on the success of therapy.5 •PSA velocity: Prostate volume increases more rapidly in patients with prostate cancer than in patients with BPH. The increase in PSA per unit of time can be used to determine the growth behavior and differentiation of prostate tissue.6 Test principle: one-step sandwich assay Streptavidin microparticle PSA in the sample Ru Biotinylated monoclonal PSA specific antibody Ruthenylated monoclonal PSAspecific antibody 9 min 9 min Ru Measurement Ru The two monoclonal antibodies used in the Elecsys total PSA are fragmented antibodies to reduce Human-Anti-MouseAntibodies (HAMA) interferences and bind to the epitopes 6b and 4b as described in literature.7 The test recognizes PSA and PSA-ACT on an equimolar basis in the range of 10 - 50 % free PSA/total PSA which are the free PSA-ratios as seen in clinical practice.8 Elecsys technology ECL (ElectroChemiLuminescence) is Roche’s technology for immunoassay detection. Based on this technology and combined with well-designed, specific and sensitive immunoassays, Elecsys delivers reliable results. The development of ECL immunoassays is based on the use of a ruthenium-complex and tripropylamine (TPA). The chemiluminescence reaction for the detection of the reaction complex is initiated by applying a voltage to the sample solution resulting in a precisely controlled reaction. ECL technology can accommodate many immunoassay principles while providing superior performance. Elecsys® total PSA assay characteristics: Testing time Test principle Traceability Sample material Sample volume Detection limit Measuring range (low end defined by lower detection limit) Repeatability Intermediate precision Functional sensitivity Expected values, healthy males (Results from the multicenter evaluation. Data on file at Roche.) Order information: Material Elecsys® total PSA Elecsys® total PSA CalSet PreciControl Tumormarker or PreciControl Universal Diluent Universal References: 1 Butch, A.W., Crary, D., Yee, M. (2001). Analytical performance of the Roche total and free PSA assays on the Elecsys 2010 immunoanalyzer. Clin. Biochem.; 35, 143-145. Not for distribution in the USA. COBAS, COBAS E, ELECSYS and LIFE NEEDS ANSWERS are trademarks of Roche. ©2011 Roche Roche Diagnostics Ltd. CH-6343 Rotkreuz Switzerland www.cobas.com 18 min. One-step sandwich assay Standardized against the Stanford Reference Standard/WHO 96/670 (90 % PSA-ACT + 10 % free PSA) Serum, Li-heparin, K 3-EDTA and sodium citrate plasma. When sodium citrate is used, the results must be corrected by + 10 % 20 µL 0.002 ng/mL (Elecsys® 2010 and cobas e 411 analyzer) 0.003 ng/mL (E 170 and cobas e 601, e 602 modules) 0.002 - 100 ng/mL (Elecsys® 2010 and cobas e 411 analyzer) 0.003 - 100 ng/mL (E 170 and cobas e 601, e 602 modules) 1.8 - 2.5 % cobas e 601 / e 602 modules, E 170: 2.9 - 4.4 % Elecsys® 2010 and cobas e 411 analyzers: 1.4 - 3.7 % cobas e 601 / e 602 modules, E 170: 2.4 - 3.8 % Elecsys® 2010 and cobas e 411 analyzers: 0.030 ng/mL Age (years) Median (ng/mL) 95th percentile (ng/mL) 0.57 1.4 < 40 0.59 2.0 40 - 49 0.75 3.1 50 - 59 1.65 4.1 60 - 69 1.73 4.4 ≥ 70 Product configuration 100 tests 200 tests (only for cobas e 601, e 602 and E 170) Material number 04641655 190 04491734 190 4 x 1 mL 2 x 3 mL each 2 x 3 mL each 2 x 16 mL sample diluent or 2 x 36 mL sample diluent 04485220 190 11776452 122 or 11731416190 11732277 122 or 03183971 122 2 Zhang, W.M., Leinonen, J., Kalkkinen, N., Dowell, B., Stenman, U.H. (1995). Purification and Characterization of Different Molecular Forms of Prostate-Specific Antigen in Human Seminal Fluid. Clin Chem; 41, 1567-1573. 3 Nadler, R.B., Humphrey, P.A., Smith, D.S., Catalona, W.J., Ratliff, T.L. (1995). Effect of inflammation and benign prostatic hyperplasia on elevated serum prostate specific antigen levels. J. Urol.; 154, 407-13. 4 National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Use of Tumor Markers in Testicular, Prostate, Colorectal, Breast, and Ovarian Cancers (2008). Clin. Chem.; 54, e11-e79. 5 Partin, A.W., Pound, C.R., Clemens, J.Q., Epstein, J.I., Walsh, P.C. (1993). Serum PSA after anatomical radical prostectomy. The Hopkins experience after 10 years. Urol. Clin. North Am.; 20, 713-725. 6 Semjonow, A., Schmid, H.P. (2002). The rise and fall of PSA: clinical implications of prostate specific antigen kinetics. Urol. Res.; 30, 85-88. 7 ISOBM TD-3 International Workshop on Monoclonal Antibodies against PSA (1999). Tumor Biology; 20, Suppl. 1. 8 Roddam, A.W., Rimmer, J., Nickerson, C., Ward, A.M. (2006). Prostate-specific antigen: bias and molarity of commercial assays for PSA in use in England. Ann Clin Biochem; 43, 35-48.
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