auto-creatinine liquicolor

Transcription

1 Design Verification auto-creatinine liquicolor Contents 1 Introduction Imprecision Linearity and Detection Limit Linearity Sensitivity Comparison of Methods Stability Accelerated Stress...5 Recovery in Control Sera Real Time Stability...6 Recovery of Control Sera...6 Linearity Interferences Traceability...8 Format: /8 valid of

2 1 Introduction The performance characteristics of auto-creatinine liquicolor have been tested and documented in order to verify its clinical usefulness and compliance with the essential requirements of directive 98/79/EC. 2 Imprecision The imprecision (within-run and day-to-day) of auto-creatinine liquicolor was calculated from six determinations on five consecutive days. Precision level low, medium and high control sera were employed as sample material. The tests were run on different analyzers. AUTOHUMALYZER 900S+ Analyte concentration Intra-assay Inter-assay () SD () %CV SD () %CV HumaStar 300 Analyte concentration Intra-assay Inter-assay () SD () %CV SD () %CV HITACHI 717 Analyte concentration Intra-assay Inter-assay () SD () %CV SD () %CV Linearity and Detection Limit 3.1 Linearity The linearity of auto-creatinine liquicolor was controlled by employing a high concentration pool serum successively diluted with phys. saline. The analysed concentrations were compared with the theoretical concentrations obtained from a linear regression. Deviations of measured against theoretical concentrations are expressed in absolute and relative values. Linearity was assumed within an accepted deviation of 5 %. As an example data measured on the AUTOHUMALYZER 900S+ are reported. AUTOHUMALYZER 900S+ 2-shot High Pool Content (%) Analytical Regressed Deviation from Regression Line (%) Design Verification and Product for auto-creatinine liquicolor 2/8

3 35 LINEARITY Linear Regression Error Bars = ± 2SD 30 MEASURED ANALYTE CONCENTRATION (mg/dl HIGH POOL CONTENT (%) Comparable results were obtained with the 1-shot kinetic procedure on other analyzers, e. g. HumaStar shot High Pool Content (%) Analytical Regressed Deviation from Regression Line (%) The claimed linearity of 15 was always well achieved, also with the working reagent procedure. Design Verification and Product for auto-creatinine liquicolor 3/8

4 3.2 Sensitivity A 20-fold determination of a 0 sample (phys. saline) on a Hitachi 717 analyzer revealed a mean of -0,03 with SD of A calculation of the analytical sensitivity based on the formula: analytical sensitivity = abs. mean + 3SD, therefore yields a value of 0.12 creatinine. 4 Comparison of Methods auto-creatinine liquicolor has been compared against a commercially available creatinine methods. Control sera as well as patient samples have been employed in the comparison. The results have been evaluated by a main component analysis. The linear regressions obtained for serum samples could be described as follows: CREATININE liquicolor (X) / auto-creatinine liquicolor (Y) (Hitachi 717) N =58 Y = x r = Method Comparison Test Reference Roche Creatinine (X) / auto-creatinine liquicolor (Y) (Hitachi 717) N =58 Method Comparison Y = x r = Test Reference The methods showed a very good agreement and no significant deviation could be observed. Design Verification and Product for auto-creatinine liquicolor 4/8

5 For plasma samples, EDTA- and heparinised plasma samples were assayed. The results have been evaluated by a main component analysis. The linear regressions obtained could be described as follows: Olympus Creatinine (X) / auto-creatinine liquicolor (Y) (Olympus AU400) N = 107 Y = x R = Both methods showed very good agreement. Since the Olympus reagent is cleared for use with plasma samples, we conclude that plasma samples are a suitable material to be used with the HUMAN auto-creatinine liquicolor assay. 5 Stability 5.1 Accelerated Stress Recovery in Control Sera Commercially available control sera have been employed. The control sera have been reconstituted/prepared according to the manufacturer s instructions. Fivefold determinations of each control serum have been performed with auto-creatinine liquicolor method and after 10 days storage at 56 C, working reagent stored 13 days at 4 C and 28 days at 25 C. The means of the fivefold determinations have been calculated and compared with the values of reagent. CONTROL SERUM RECOVERY auto-creatinine Reagent auto-creatinine Reagent 10 days 56 C Control serum LOT Deviation (%) HumaTrol N # HumaTrol P # SERODOS # SERODOS plus # Precinorm # Precipath # Mean Design Verification and Product for auto-creatinine liquicolor 5/8

6 CONTROL SERUM RECOVERY auto-creatinine Working Reagent auto-creatinine Working Reagent 13 days 4 C auto-creatinine Working Reagent 28 days 25 C Control serum LOT Deviation (%) Deviation (%) HumaTrol N # HumaTrol P # SERODOS # SERODOS plus # Precinorm # Precipath # Mean Real Time Stability The stability of auto-creatinine liquicolor has been tested on real-time storage conditions over a period of 24, 26 and 27 months for three independent production lots (H016, exp. date: June 2006; H014, exp. date: April 2006; H011, exp. date: March 2006), measurements were made on Olympus AU 400. Acceptance criteria were based on the recovery of controls and linearity. Recovery of Control Sera Commercially available control sera have been employed. The control sera have been reconstituted/prepared according to the manufacturer s instructions. Twofold determinations of each control serum have been performed with auto-creatinine liquicolor reagent, which was stored at C over the duration of shelf life after initial opening. The means of the twofold determinations have been calculated and compared with the range of reagent. Design Verification and Product for auto-creatinine liquicolor 6/8

7 CONTROL auto-creatinine H016 auto-creatinine H014 auto-creatinine H 011 Target value (Refer) 24 months Target value (Refer) 26 months Target value (Refer) 27 months Control serum LOT Range Range Range HumaTrol N # HumaTrol N # HumaTrol N # HumaTrol P # HumaTrol P # SERO.plus # SERO.plus # The data support the claimed open bottle stability of 24 months. Linearity High Pool Analytical auto-creatinine (Refer) H030 Regressed Deviation from Regression Line Analytical auto-creatinine, 24 months, H016 Regressed Deviation from Regression Content (%) (%) (%) Line High Pool Analytical auto-creatinine, 26 months, H014 auto-creatinine, 27 months, H 011 Regressed Deviation from Regression Line Analytical Regressed Deviation from Regression Content (%) (%) (%) Line All results support the claimed stability of 24 months from production for the test kit. Design Verification and Product for auto-creatinine liquicolor 7/8

8 6 Interferences Interference by hemoglobin, bilirubin, triglycerides and ascorbate have been studied by adding known amounts of the potentially interfering substance to a known sample. Recoveries have been analysed according to the method of Glick et al. (Clin.Cem. 1986, ). The results are summarised in the following table. Hemoglo bin Analyt. Dev. % Bilirubin Analyt. Dev. % Triglyceri des Analyt. Dev. % Ascorbate Analyt Glick Dev. % The test is significantly interfered with (deviation of >10%) by hemoglobin >200 or bilirubin >12. Triglycerides up to 2500 or ascorbate up to 20 do not significantly interfere with this test. Samples with highly pathological bilirubin concentrations (> 12 ) should therefore be avoided. 7 Traceability auto-creatinine liquicolor is calibrated with AUTOCAL, which is traceable to the reference material SRM 909B level 2. Design Verification and Product for auto-creatinine liquicolor 8/8