Performance Evaluation of the HoribaABX Micros CRP 200 ...
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Performance Evaluation of the HoribaABX Micros CRP 200: Comparison with DPC Immunolite C reactive protein assay Bruce H. Davis*, Kathleen T. Davis*, Karen Becker* *Trillium Diagnostics, LLC and Maine Medical Center Research Institute, Scarborough, Maine 04074 USA INTRODUCTION HoribaABX Diagnostics has developed a new generation Micros CRP analyzer, the Micros CRP 200, which extends the linearity range of C-Reactive Protein (CRP) measurements over the first instru- ment to provide both a complete blood count (CBC) with a three part differential and a whole blood quantitative CRP determination. The principle of CRP measurements is based upon an immunotur- bimetric method using latex beads coated with a monoclonal antibody with anti-CRP specificity. We have conducted a performance evaluation of the linearity, sensitivity, precision, clinical performance, and carryover of the new Micros CRP 200 instrument. METHODS Precision of CRP analysis was performed by replicate (N=10) determinations on K3-EDTA anticoagulated whole blood on samples with CRP values in the range of 0.7 – 16.3 mg/dL, as well as paired duplicate analysis on 125 samples with a range of <0.05 – 39 mg/dL. Linearity was evaluated by mixing of clinical samples and spiking of normal blood with CRP control material. The stability of results was studied in blood samples held at room temperature and refrigerated conditions over a 72 hour period. The correlation of CRP measurements of the ABX Micros CRP was compared to the DPC Immulite high sensitivity CRP assay (immunoassay) and the original ABX Micros CRP assay (immunoturbimetric) on 125 clinical samples. Performance of the Micros CRP was also evaluated for specimen carryover and performance on clinical samples with lipemia, hyperbilirubinemia, hemolysis, monoclonal gammopathy, and thrombocytopenia. Carryover was examined by triplicate analy- sis of blood specimens with high CRP levels followed by one with normal low CRP levels. RESULTS PRECISION Clinical blood samples identified as having variable levels of CRP were analyzed ten times within a two hour period to examine imprecision or repeatability in blood samples. The ave- rage, coefficient of variation, and standard deviation of the replicate measurements for each sample were calculated. The following claim shall be made for precision in normal human blood for the measurement of C reactive protein: LINEARITY Linearity of the ABX Micros CRP 200 is demonstrated by serial 1:2 dilution of the clinical blood samples. The dotted line indicates equivalence between the expected and measured C Reactive Protein. Measurements were made on whole blood (left panel) and plasma (right panel) sam- ples. CARRY-OVER Results provided are extremely satisfactory. In order to provide for eventual possibilities within the laboratory environment the following claims shall be made: Carryover between specimens and the measurement of C Reactive Protein is less than 0.5%. CONCLUSION The data shows excellent correlation between results measured on HoribaABX Micros CRP 200 versus the predicate ABX Micros CRP and DPC Immulite methods. No intermethod bias was observed among and between all the methods, nor between the specimen type of whole blood compared to plasma/serum. The HoribaABX Micros CRP 200 demonstrated performance highly suitable for the clinical practice. In particular the ease of use, small sample volume (18 microliter), increased linearity range, and rapid turnaround (<5 minutes for CBC and CRP) makes the instrument of likely utility in the near patient testing area, including intensive care units in adults and infants, and office laboratories, parti- cularly those of pediatricians, cardiologists, rheumatologists and infectious disease specialists. The combination of CBC parameters with other laboratory determinations traditionally in the chemistry area may be a new trend in laboratory hematology. STABILITY The results indicate a sample stability claim of 72 hours with storage of either room temperature and 4° C for C Reactive Protein determinations. ACCURACY A total of 125 clinical samples were obtained from patients with at least 85 samples containing CRP covering the widest possible range of values. Sample were processed within a 4 hour period for the different methods, which included the HoribaABX Micros CRP 200, ABX Micros CRP, and the DPC Immulite high sensitivity CRP methods. Comparison C Reactive Protein levels on HoribaABX Micros CRP 200 compared the ABX Micros CRP and CPC Immulite methods with 125 clinical samples. Comparison C Reactive Protein levels on HoribaABX Micros CRP 200 compared the ABX Micros CRP and CPC Immulite methods with 41 clinical samples with values less than 1.5 mg/dL Comparison of the 31 samples split into whole blood and plasma aliquots and then analyzed on the HoribaABX Micros CRP. No significant bias was observed in the range of 0 – 13.5 mg/dL. Bias plot of the 125 samples analyzed on the HoribaABX Micros CRP 200 compared to the other two methods of C Reactive Protein measurements. No significant bias was observed in the range of 0 – 38 mg/dL. ANTICOAGULANT EFFECT HoribaABX Micros CRP 200 performance was examined with different anticoagulants to deter- mine if the mode of blood collection has any effect on the results. C Reactive Protein measurements are similar with the three anticoagulants studied. No inter- ference with the measurements was found with any of the anticoagulants. Thus, CRP measu- rements can be performed with specimens collected in EDTA, citrate, or heparin anticoagulant tuhes.
Transcript of Performance Evaluation of the HoribaABX Micros CRP 200 ...
Performance Evaluation of the HoribaABX Micros CRP 200:Comparison with DPC Immunolite C reactive protein assay
Bruce H. Davis*, Kathleen T. Davis*, Karen Becker**Trillium Diagnostics, LLC and Maine Medical Center Research Institute, Scarborough, Maine 04074 USA
INTRODUCTION
HoribaABX Diagnostics has developed a new generation Micros CRP analyzer, the Micros CRP 200, which extends the linearity range of C-Reactive Protein (CRP) measurements over the first instru-ment to provide both a complete blood count (CBC) with a three part differential and a whole blood quantitative CRP determination. The principle of CRP measurements is based upon an immunotur-bimetric method using latex beads coated with a monoclonal antibody with anti-CRP specificity. We have conducted a performance evaluation of the linearity, sensitivity, precision, clinical performance,and carryover of the new Micros CRP 200 instrument.
METHODS
Precision of CRP analysis was performed by replicate (N=10) determinations on K3-EDTA anticoagulated whole blood on samples with CRP values in the range of 0.7 – 16.3 mg/dL, as well as pairedduplicate analysis on 125 samples with a range of <0.05 – 39 mg/dL. Linearity was evaluated by mixing of clinical samples and spiking of normal blood with CRP control material. The stability ofresults was studied in blood samples held at room temperature and refrigerated conditions over a 72 hour period. The correlation of CRP measurements of the ABX Micros CRP was compared to theDPC Immulite high sensitivity CRP assay (immunoassay) and the original ABX Micros CRP assay (immunoturbimetric) on 125 clinical samples. Performance of the Micros CRP was also evaluated forspecimen carryover and performance on clinical samples with lipemia, hyperbilirubinemia, hemolysis, monoclonal gammopathy, and thrombocytopenia. Carryover was examined by triplicate analy-sis of blood specimens with high CRP levels followed by one with normal low CRP levels.
RESULTS
PRECISION
Clinical blood samples identified as having variable levels of CRP were analyzed ten timeswithin a two hour period to examine imprecision or repeatability in blood samples. The ave-rage, coefficient of variation, and standard deviation of the replicate measurements for eachsample were calculated.
The following claim shall be made for precision in normal human blood for the measurementof C reactive protein:
LINEARITY
Linearity of the ABX Micros CRP 200 is demonstrated by serial 1:2 dilution of the clinical bloodsamples. The dotted line indicates equivalence between the expected and measured C ReactiveProtein. Measurements were made on whole blood (left panel) and plasma (right panel) sam-ples.
CARRY-OVER
Results provided are extremely satisfactory. In order to provide for eventual possibilities withinthe laboratory environment the following claims shall be made: Carryover between specimens and the measurement of C Reactive Protein is less than 0.5%.
CONCLUSION
The data shows excellent correlation between results measured on HoribaABX Micros CRP 200 versus the predicate ABX Micros CRP and DPC Immulite methods. No intermethod bias was observedamong and between all the methods, nor between the specimen type of whole blood compared to plasma/serum.
The HoribaABX Micros CRP 200 demonstrated performance highly suitable for the clinical practice. In particular the ease of use, small sample volume (18 microliter), increased linearity range, andrapid turnaround (<5 minutes for CBC and CRP) makes the instrument of likely utility in the near patient testing area, including intensive care units in adults and infants, and office laboratories, parti-cularly those of pediatricians, cardiologists, rheumatologists and infectious disease specialists. The combination of CBC parameters with other laboratory determinations traditionally in the chemistryarea may be a new trend in laboratory hematology.
STABILITY
The results indicate a sample stability claim of 72 hours with storage of either room temperatureand 4° C for C Reactive Protein determinations.
ACCURACY
A total of 125 clinical samples were obtained from patients with at least 85 samples containingCRP covering the widest possible range of values. Sample were processed within a 4 hourperiod for the different methods, which included the HoribaABX Micros CRP 200, ABX MicrosCRP, and the DPC Immulite high sensitivity CRP methods.
Comparison C Reactive Protein levels onHoribaABX Micros CRP 200 compared theABX Micros CRP and CPC Immulitemethods with 125 clinical samples.
Comparison C Reactive Protein levels onHoribaABX Micros CRP 200 compared theABX Micros CRP and CPC Immulitemethods with 41 clinical samples withvalues less than 1.5 mg/dL
Comparison of the 31 samples split intowhole blood and plasma aliquots and thenanalyzed on the HoribaABX Micros CRP.No significant bias was observed in therange of 0 – 13.5 mg/dL.
Bias plot of the 125 samples analyzed on theHoribaABX Micros CRP 200 compared tothe other two methods of C Reactive Proteinmeasurements. No significant bias wasobserved in the range of 0 – 38 mg/dL.
ANTICOAGULANT EFFECT
HoribaABX Micros CRP 200 performance was examined with different anticoagulants to deter-mine if the mode of blood collection has any effect on the results.
C Reactive Protein measurements are similar with the three anticoagulants studied. No inter-ference with the measurements was found with any of the anticoagulants. Thus, CRP measu-rements can be performed with specimens collected in EDTA, citrate, or heparin anticoagulanttuhes.
