Cerba Healthcare Belgium, afdeling CRI
Abstract Bachelor Project 2019-2020: Comparison of three RPR tests for syphilis screening
Syphilis is a sexually transmitted disease and is caused by the bacterium Treponema pallidum. To detect the disease, there are two tests: the non-treponemal test that is based on the tracing of non-treponemal antigens in serum and the treponemal test that searches treponemal antigens.
The aim of this project is to evaluate if a new non-treponemal test from Selinion Medical is transparant with two current tests of the companies Werfen and Spinreact. This is because an alternative is needed to the test of the company Werfen that will no longer be produced from June onwards.
The three assays were easy to perform and they all use a small sample volume. To perform the comparison, 40 samples are required. The results of these samples are already known and there is an equal amount of positives and negatives. Al 40 samples were tested in parallell by all three tests.
The results were split into two categories. The first category is an overview of the data. When comparing the three test the data was parallel to each other. Due to the use of titres, the results are semi-quantitative. We observed a maximum deviation of one titre between tests, considered the biologist of the CRI-lab. In every comparison in a medical lab, it’s important to check if deviations don’t have a clinical impact on the patient, even if there are only small deviations. In this project there were no such deviations detected. We can therefore conclude that the three tests are transparent for clinical evaluation of syphilis.
The second category is ease of use, which is an important point in the comparison of the different tests, as it can impact workload or result in errors. Every assay has their advantages and disadvantages, but overall we could not observe any issues that might result in error or significantly added workloads. The new kit is from a reliable company and is cheaper, which is an important factor, given transparent clinical decisions and workload.
Based on the results and the ease of use, all assays are considered transparent so both labs can switch to the new test.
Abstract Bachelor Project 2017-2018: Validation of fecal markers on the ThunderBolt® Analyzer
Preventive healthcare has become more important in recent years.That is why CRI has partnered with biopredix to give patients more inside into intestinal health.
This can be done by doing a gut screening withs includes measuring secretory IgA, beta-defencine, zonulin, pancreatic elastase, ... These parameters are still measured manually now and are really labor-intensive. Therefore CRI decided to try to automate them on the ThunderBolt® Analyzer. Before this transition can be completed, A validation process needed to be conducted on the different parameters. This was done by using fecal samples collected from apparently heathy volunteers. These were aliquoted and measured on the ThunderBolt® Analyzer. At the same time also samples with a known concentration were measured. The results were then processed on Excel by using a four parameter fit curve.
For some of the parameters additional tests need to be conducted to find a working protocol to validate them completely.
Abstract bachelorproef 2016-2017: Validation of the new test active B12 and a new generation of reagent for anti-HBs on Architect i2000SR
Active vitamin B12 is a new parameter that will be determined in the lab. For the determination of anti-HBs there is a new generation of reagent. Since CRI is ISO15189 accredited, validation must be performed in these cases. Anti-HBs is an already existing test performed on the Architect i2000SR from Abbott. Active B12 will also be performed on the Architect i2000SR.
The determination of active B12 can be useful since the determination of total B12 doesn’t always detect a deficiency. The highest amount of total B12 is biologically inactive and can mask a low level of active B12. Patients will miss their diagnosis when only total B12 is determined. That’s why CRI has decided to implement the determination of active B12.
A healthcare provider or a medical laboratory worker must be immune to the hepatitis B virus. Therefore, the anti-HBs titer is determined. The determination of anti-HBs can also be useful for patients with hepatitis B. When the antibodies can be detected in blood, the infection with the virus is over.
For both validations the precision and accuracy will be determined with the 5x4 method. Also the limit of quantification will be verified for both tests. For anti-HBs a cross validation will be performed between the current generation and the new generation of reagent. The results will be evaluated using a Bland and Altman plot and Passing Bablok regression. For active B12 the reference ranges and stability in the fridge will be verified. The last validation test is making a dilution series to verify the linearity of the calibration curve.
Both parameters are precise and accurate according to the criteria of Abbott and the European Medicines Agancy (EMEA). Both limits of quantification are accepted according to Abbott and EMEA. The cross validation has shown that there is a systematic and proportional error on the new generation of reagent for the determination of anti-HBs. The reference ranges for active B12 are accepted according to Clinical & Labaratory Standards Institute. Active B12 was shown to be stable for four days in the fridge. Finaly, the calibration curves of both tests were shown to be linear.
Based on the findings of the validations, active B12 will be implemented in the laboratory. Additional validation is required for anti-HBs since the new generation reagent is not transparent with the current generation.
Abstract bachelorproef 2015-2016: Validatie van STA-R MAX® Stago analysers voor routine coagulatie parameters
Quality assurance has become the most important metric in routine laboratory practice in recent years. Therefore CRI decided, in their continuous pursuit of excellence, to replace their current coagulation analyzer STA-R Evolution in favor of the next-generation STA-R MAX®.
Before the transition process can be completed a validation protocol to ensure STA-R MAX® performance will be executed. At the start of the study it is known that STA-R Evolution® performs correctly and was therefore used as a reference instrument for this study. This validation will evaluate two STA-R MAX® analyzers by comparing results with the current STA-R Evolution®.
Measurements are conducted using the same samples under the same conditions. Coagulation parameters tested are Protrombine Time (PT), Activated Partial Trombine Time (aPTT), Fibrinogen (FBG) and D-Dimer (D-Di). To test STA-R MAX® ability for accurate analysis, a series of measurements are made from samples for each of the four parameters. The results of these measurements allow calculation of the precision, bias and allowable total error of the instrument. Additional tests are conducted to observe STA-R MAX® ability to detect and measure different samples under various conditions such as Carry-over and Cap-piercing.
Clinical measurement differences between STA-R MAX® and STA-R Evolution® are validated according to criteria of Ricos and the STA-R series manufacturer STAGO. Validation results for STA-R MAX® are shown to be acceptable. Evaluating these results CRI decides to implement STA-R MAX®in favor of its predecessor STA-R Evolution®.
Samenvatting eindwerk 2014-2015: Validation and implementation of MALDI -TOF MS in a clinical microbiology lab
In the clinical microbiology laboratory of CRI the identification of bacteria is based on current methods, quick tests and selected media. These methods have some cons. The identification of bacteria takes very long. The methods needs many hours of incubation. A second disadvantage is the cost because there are many different tests required.
Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF MS) offers the possibility of accurate, rapid, inexpensive identification of bacteria in clinical microbiology laboratory. This technique is an ionization method which allows desorption of proteins from different microorganisms. Ions will be separated and detected by their molecular mass. The bacteria are identified on the basis of the mass/charge ratio (m/z). This proceeds to a spectrum. This spectrum can be compared to a database. There will be an agreement between the measured spectrum and the reference spectrum. This is linked to the correct microorganism.
The validation results will be compared with American Type Culture Collection (ATCC) strains, Extern Quality Control (EQC) strains and routine germs.
A validation plan was worked out and containing the following criteria:
- Accuracy and reliability
- Effect of culture age on reliability
- Stability of germ on target covered or uncovered spots with matrix
- Formic acid extraction on yeasts
- Streptococcus species in a bacterial solution
All of the criteria of the MALDI-TOF method were good. The identification of bacteria and yeasts by MALDI-TOF MS proved to be extremely reliable and reproducible. But there are still some limitations noticed in our validation. These are very important in the daily operation of a routine microbiology lab. The two most important constrains are the Shigella limitation and the S. pneumoniae/mitis/oralis limitation. The efficacy of MALDI-TOF MS identification of Candida species appeared to be higher with the 70% formic acid extraction. So the formic acid extraction of yeast will be included as a standard procedure in the labprotocol. The bacterial solution of Streptococcus was not optimal. Further research is recommended.
As a final conclusion, we can conclude that the identification of bacteria and yeast with MALDI-TOF MS is a great progress in a clinical microbiology. The benefits are low cost, speed of execution, reliability and reproducibility.
Industriepark Zwijnaarde 3
Sarah De Baets