Evaluation of the Coris Clostridium K-SeT test. In comparison with Alere C. diff quik chek test

Transcription

1 Evaluation of the Coris Clostridium K-SeT test In comparison with Alere C. diff quik chek test 13/03/2012 Coris BioConcept

2 Report of Clinical Performance Study of Clostridium K-SeT Coris BioConcept test in comparison with Alere C. diff quik chek Truthful and Accurate Statement I, Polly Shepperd certify that, in my capacity as trainee biomedical scientist, I believe to the best of my knowledge, that all data and information submitted in the above referenced Report of Clinical Performance Study of Coris BioConcept Clostridium K-SeT are truthful and accurate and that no material fact has been omitted. These data belong to Coris BioConcept, therefore they can be used for any commercial purpose. Signature: Date: 13/03/12

3 Report of Clinical Performance Study of Clostridium K-SeT Coris BioConcept test in comparison with Alere C. diff quik chek Place where test was performed: Poole Microbiology Laboratory, Poole Hospital NHS Foundation Trust, Longfleet Road, Poole, Dorset, BH15 2JB. Information about the trial Site Poole Microbiology is a general microbiology laboratory in a district hospital processing samples from both hospital and GP patients. Approximately 330,000 samples are processed in the laboratory per year. The department has CPA accreditation and is HPC approved for training. Lead Investigator, Responsible Person of the investigation: Polly Shepperd (James Hobbs supervising) Investigator : Polly Shepperd Period of Testing (including the estimated end date) : 20/12/ /02/12 Product evaluated: Batch Number of kit: 25383L1116 Batch Number of sticks: 1K20L1121 Batch Number of extraction: 2J06K1114 Comparator(s) Method(s) : Batch Number of kit: 22/12: /01: Brief description of that reference methods used : The C. diff quik chek is an immunoassay test which detects glutamate dehydrogenase (GDH) in stool samples. 500 l of diluent is dispensed into a small tube along with one drop of conjugate and 25 l of stool sample. The diluent/conjugate solution is then mixed

4 and 400 l is transferred to the sample well and incubated at room temperature for 15 minutes next 300 l of wash buffer is added to the reaction window and once absorbed two drops of substrate are added. After 10 minutes the result can be observed as two blue lines, one for the control and one for the positive GDH antigen. Study Objective: To compare the Coris BioConcept test with the Alere test for detecting Clostridium difficile. Sample type tested and collection method: Stool samples Study Population: Liquid or semi-liquid stool samples of in-patients or GP patients aged over 65 over a seven week time-period. Samples collected (number of samplings to test) : 100 Methods employed : Stool samples were examined for the presence of Clostridium difficile using both the Alere and Coris tests. The enclosed protocols for each kit were followed. If either kit was positive for GDH indicating a possible C. difficile then the sample was then tested using PCR. If only one of the kits was positive then the sample was also tested using PCR. If PCR was positive and one kit missed the C. difficile then culture methods would be used. Trials findings summary (at the end of study) : Alere Test POS NEG total Coris Test POS NEG total

5 Sensitivity : Specificity : Reliability : Positive Predictive Value Negative Predictive Value 100% (TP/ (TP+FN)) 98.9% (TN/ (TN+FP)) 99% (TN+TP)/Total) 87.5% (TP/(TP+FP)) 100% (TN/ (TN+ FN)) Conclusion: The Coris BioConcept kit gave good results with very high sensitivity results (100%) in this study. The specificity results were also high (98.9%) with one more false positive than the Alere kit. The Coris BioConcept kit was easy to use and has the benefit of being quicker to obtain results than the Alere kit. The fact that there is only one step to the Coris BioConcept kit also makes it easier to use. However, there are two problems that if amended I feel would improve the Coris BioConcept kit. The first problem is that the kit is almost identical to the Coris BioConcept Rota/Adeno kit, which may lead to mistakes with using the wrong kit. If the C. diff kit could be a different colour this would solve any potential confusion. The second problem is that if the stool sample is liquid or semi-liquid it must be pipetted into the extraction solution and no pipettes were provided. Using normal pipettes it was difficult to pick up the stool samples, as they were usually mucoid so the provision of pipettes or pipette tips with wider bores would make this test far more efficient.

6 Table 1. Results for Each Specimen (No. 1) A/ The status of samples is defined by the reference method used and should be notified as : N: Negative, P: Positive, TN: True Negative, TP: True Positive, FN: False Negative, FP: False Positive B/ Legend of the here-under table : Clostridium difficile results for 100 examined specimens using Coris and Alere kits. Results verified using GeneXpert PCR. SN Sample Number. Alere Test Coris Test Results SN Sample Number Alere Test Coris Test TP TP P N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N FP N N N N N N N FP FP N N N N N N N TP TP P N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N TP TP P N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N TP TP P N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N Results N N N N N N

7 N N N N N N N N N N N N N N N N N N FP FP N FP FP N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N