OLV Ziekenhuis Waregem - klinisch laboratorium
Abstract Bachelor project MLT 2020-2021: Evaluation of assays for the detection of antibodies against systemic and organ specific autoimmune diseases on the Alegria®
O.L.V van Lourdes hospital in Waregem wants to perform additional assays for the detection of antibodies against various autoimmune diseases in-house on the Alegria®. The aim of this paper is to evaluate assays for the detection of various auto-immune diseases. The parameters that were evaluated are anti-cardiolipin IgG and IgM, anti-cyclic citrullinated peptide antibodies (anti-CCP), anti-tissue-transglutaminase IgA and anti-deamidated gliadin IgG.
The detection of anti-cardiolipin IgG and IgM antibodies is used for the detection of the anti-phospholipid syndrome. Anti-cyclic citrullinated peptide antibodies is an biomarker for rheumatoid arthritis. The last two parameters, anti-tissue-transglutaminase IgA and anti-deamidated gliadin IgG can be detected for gluten intolerance or celiac disease.
The assays are evaluated for precision, accuracy and method comparison. Precision is performed by two different experiments. The first one is a within-run imprecision, the other one is a between-day imprecision. For the performance of the within-run experiment a positive and low positive sample were selected. Three consecutive measurements are to be performed on the Alegria®, under the same conditions and in the same run. Between-day imprecision will be performed with the same samples, under the same conditions but on different days. The results obtained for these two imprecision experiments are used to calculate the mean, the standard deviation and the coefficient of variation (CV). The calculated CV will be compared to predefined criteria form 1) the manufacturer and 2) the Ghent University Hospital.
For evaluation of accuracy external quality control materials were used if possible. Patiënt samples were added for additional data. The same datasets were used for method comparison against the routine method (patient samples) or expected value (external quality control materials) respectively. Method comparison was done by making cross tables for all assays with qualitative comparison and evaluation of concordance. Any discordancies are to be evaluated closely.
The within-run experiment results for anti-cardiolipin IgG and anti-cardiolipin IgM do not meet with the predefined criterion of the manufacturer. The CV for anti-cardiolipin IgG do not succeeds the criterion of 1/3 of the error. The results from the between-day imprecision there is only one results that succeeds for the criterion of the manufacturer. All the other CV’s didn’t meet the criterion of the manufacturer. The 1/3 error didn’t succeeds for the sample with the high value for anti-cardiolipin IgG and for the sample with the low value for anti-cardiolipin IgM. For anti-CCP both samples didn’t succeeds for the criterion of the manufacturer. The criteria of the hospital did succeeds for the within-run experiment and the between-day imprecision. Expect for the sample with the low value didn’t succeeds the criterion of the 1/3 error. The results for anti-TTG IgA do meet with the criterion of the manufacturer and the criteria of the hospital. For the experiment there was used a sample with a negative results. This sample didn’t meet any of the predefined criteria. The last parameter is anti-deamidated gliadin IgG. Three CV’s didn’t meet with the criterion of the manufacturer. All samples succeeds for the criterion of the total error.
For the accuracy for anti-cardiolipin IgG and anti-cardiolipin IgM there is one sample that is discordance with the target response. The sample that is discordance is an external quality material. For anti-CCP there are three samples who isn’t concordance with the results of the routine method. One of the samples is an external quality material, the other two are patient samples of the routine method. One of the samples is repeated with a third method. The results of the third method is concordant with the results obtained from the Alegria®. The results obtained for anti-TTG IgA there are two samples that are discordant with the routine methods. The last biomarker is anti-deamidated gliadin IgG. For this biomarker there is one result that is discordant with the routine method. The method comparison is evaluated using cross tables. Every cross table shows how many sample are discordant and how many samples are concordant for both methods. For anti-cardiolipin IgG and anti-deamidated gliadin IgG there is just one sample that is discordant. For anti-cardiolipin IgM there are only concordant results. For anti-TTG there are two results that are discordant with the routine method. for the last biomarker there are three results that are discordant with the routine method.
In conclusion all assays under evaluation on the Alegria® show acceptable performance for precision, accuracy and in the method comparison except for anti-tissue-transglutaminase IgA and anti-deamidated IgG, as there is additional testing needed for accuracy. For these two parameters there were insufficient control materials available during the testing period.
Abstract Bachelor project 2019-2020: Comparison of two fecal occult blood rapid tests (FOBT) with the current test
Colon cancer is the third most common cancer in Belgium. Screening with a fecal occult blood test is the best way to reduce the number of deaths by early detection. There are two types of tests, guaiac or immunochemical based tests. The current test used wil not be produced anymore so the lab needs a new kit. All three kits are immunochemical based tests.
The current FOBplus® (bioMérieux) test will be compared with two new kits (HEMDETECT® IMMO i-FOB and SD FOB® by bioline)
Twenty tests positive with FOBplus® from bioMérieux and twenty tests negative with FOBplus® from bioMérieux were compared with HEMDETECT® IMMO i-FOB and SD FOB® by bioline. Specificity, sensitivity, positive predictive value and negative predictive value were calculated and compared.
The specificty, sensitivity, positive predictive value and negative predictive value were respectivly 78,9%; 90,0%; 88,2% and 81,2% for the HEMDETECT® IMMO i-FOB and 100,0%; 85,0%; 86,4% and 100,0% for the SD FOB® by bioline test.
The SD FOB® by bioline test is the best choice to replace the FOBplus® by bioMérieux test.
Colon cancer, fecal occult blood test
Abstract Bachelor project 2019-2020: Description of a local COVID-19 cluster during the pandemic using direct (RT-PCR) and indirect (antibody detection) techniques
The aim of this research is to describe a specific cluster of 33 persons who were confronted with coronavirus disease 2019 (COVID-19) using various analysis techniques. The analyses were performed in the laboratory of the O.L.V of Lourdes hospital in Waregem. In this way, a broader picture of the evolution of the disease and the impact on a population is obtained.
COVID-19 is a disease originating from severe acute respiratory syndrome – Coronavirus – two (SARS-COV-2), which is a virus that caused a pandemic in 2019 that is still very pervasive today. SARS-COV-2 causes COVID-19 which is characterized by numerous symptoms such as fever, cough, muscle pain. Direct analysis techniques such as realtime PCR can be used to determine whether or not a person is positive for SARS-COV-2. In addition, it can also be determined whether a person has already encountered the pathogen, by detecting the antibodies against SARS-COV-2 using indirect analysis techniques.
In this study, serum samples were collected from 32 persons who were present on a trip and one person who could be the index case. Multiple samples were collected over time so that the evolution of the antibodies could be monitored. These samples were examined for the presence of antibodies IgG and IgA against SARS-COV-2 using the enzyme-linked immuno sorbent assay (ELISA) EUROIMMUN kit. In addition, some of the subjects (n=8) also had a nasopharyngeal swab collected to determine whether they had COVID-19 at the time of symptoms. The analysis was performed using a realtime reverse transcription polymerase chain reaction kit from the company OSANG Healthcare on the Elite Ingenius analyzer (Elitech). The analysis targets three genes, namely the RdRp-gene, the E- and N gene. For one subject with discrepant serology results versus the experienced symptoms, WANTAI SARS-CoV-2 Ab ELISA (Beijing, China) and the Cobas® SARS-CoV-2 test (Basel, Switzerland) were also performed.
The results showed that 78% of the persons had symptoms within one day after the bus trip. The most common symptoms were fever (55%), cough (47%), general weakness (42%) and headache (33%).
On the basis of the results of the ELISA kits, there could be established that 32 of the 32 persons who were present on the trip have had SARS-CoV-2 infection. In each case, an increased ratio of IgA was first detected, after which the ratio of IgG started to increase. Eight persons of the group were analyzed by PCR, everyone was positive for the three genes.
In conclusion, SARS-CoV-2 is a highly contagious virus since 33 out of 33 subjects have experienced SARS-CoV-2. Both the disease course and the antibody development over time was variable. One person with seroconversion did not develop any symptoms. The study subjects will be followed further in time to evaluate antibody kinetics.
Abstract Bachelor project 2017-2018: Evaluation of the Atellica NEPH 630 nephelometer for protein chemistry
Determination of proteins in serum, urine and cerebrospinal fluid make it possible to make an estimation of the physiological state of a patient and can therefore be important for diagnosis or follow-up of several diseases. At the department of Laboratory Medicine at the Hospital of Waregem, these important biomarkers are measured on the nephelometer IMMAGE ® 800 (Beckman Coulter, CA, USA), an old platform. A suitable nephelometer for its replacement is currently under evaluation, the Atellica NEPH 630 ® (Siemens, Erlangen, Germany).
The aim of this essay is to evaluate the Atellica NEPH 630® nephelometer and compare it to the IMMAGE 800® for a large range of assays.
Precision, bias and allowable total error are evaluated with control materials on the Atellica NEPH 630. Furthermore, patient serum, urine and cerebrospinal fluid samples are collected for determination on IMMAGE 800® and Atellica NEPH 630®. Parameters under evaluation are alpha-1-antitrypsin, alpha-1-microglobulin, albumin in serum, urine and CSF, antistreptolysin-O, Bèta-2-microglobulin, C1 esterase inhibitor, Complement 3 and 4, ceruloplasmin, haptoglobin, immunoglobulin A, G, M and immunoglobuline IgG2, 3 and 4 and rheumatoid factor.
Imprecision experiments on patient material (within-run), manufacturer’s control materials (within- and between-run) and third-party control materials (between-run) show good results as evaluated by several criteria for imprecision, bias and total error. Only one parameter, ceruloplasmin, exceeded total error specifications for manufacturer’s control materials because of bigger contributing bias (limited on-board stability). Method comparison results show overall good correlation (Rs>0.95) except for 4 parameters mainly due to limited sample numbers. Passing-Bablok regression analysis is acceptable although multiple proportional and systematic statistically significant biases were to be noted. To be highlighted is the difference for IgG subclasses 3 and 4 with major proportional biases to be noted. When consulting literature, these differences are to be expected because of historically different calibration materials. Cross table summaries of the patient samples evaluated showed no major discrepancies for all parameters, except for IgG subclasses 3 and 4 which is well known.
In all, differences between the IMMAGE 800® and Atellica NEPH 630® are within limits for nephelometric protein chemistry which makes the Atellica NEPH 630 ® suitable for routine practice. A possible switch for IgG subclasses is to be done with caution as major differences in standardization limits transferability and shows the need for reagent specific age-dependent reference intervals.
Maxime De Sloovere