diff. The major activators are ADP and leucine and inhibitors include GTP, palmitoyl CoA, and ATP. If the result is GDH positive a second test is performed to look for toxins that are produced when C. difficile include:GDH-positive, EIA-negative, CCCN-positive specimens were considered positive for toxin B-producing C. difficile disease. The device was then examined for the appearance of blue lines on the “Ag” and “Tox” sides of the reaction window. difficile GDH antigen. 3. In summary, the C. Tünetek és rizikófaktorok. . The School Aged Surveillance, Age Trends, LTCF Weekly, and LTCF Percent Positivity Reports have been discontinued. difficile, all of which were PCR positive. difficile had significantly lower body mass index than those without. If the GDH test was positive, an additional toxin A&B EIA was performed. difficile PCR assay and/or repeat GDH/Toxin testing of a subsequent sample if indicated. In current perception, GDH contributes to Glu homeostasis and plays a significant role at the junction of carbon and nitrogen assimilation pathways. Buna seara, Am fost diagnosticata cu clostridium difficile (toxina A pozitiva) si am luat tratament Metronidazol timp de 10 zile. If the GDH is positive, the next step is to perform an EIA for C. difficile were initiated versus 4/28 (14. With regards to the toxigenicity of C. GDH test positive fecal samples were tested by PCR for toxin A (tcdA) and B (tcdB) to differentiate between patients colonized with non-toxigenic C. 0%, and 72. Major risk factors for. 71/1000 patient days. Tables 1 and 2 compare the performance of GDH or toxin A/B RDT with the respective EIA. The ageWhen the results of QCC or RC-GDH+RC-Toxin A/B were used as the first step of a two-step algorithm for diagnosing CDI, QCC permitted more accurate discrimination than RC of positive or negative. In their study, Greene et al. 6%) patients with a positive NAAT and GDH test and a negative toxin A&B EIA, no antibiotics against C. The GDH test is recommended as an initial screening test because of its very high sensitivity [2, 4, 7, 9, 16], reported to be 79. Methods: We performed a retrospective cohort study evaluating all C. This was found to be a paradoxical disease;. difficile colonization (the GDH test was positive, but the toxin test was a true negative). Only in the animal kingdom is this enzyme heavily allosterically regulated by a wide array of metabolites. difficile colonization and may not require therapy but should be placed in enteric isolation regardless of treatment b. 5%) were ALERE GDH-toxinsShe has had 5 episodes of c diff, one Fecal transplant and now on the 6th episode of GDH positive but negative toxins. 9 Cases were assigned to a given hospital based on. 28 of the 246 samples (11. All the reuterin-producing lactobacilli expressed the gdh, pdh30 and pdh1734, except Lb. Clostridium difficile este recunoscut ca principala cauză a colitei intraspitaliceşti la pacienţii. difficile FIA you can detect GDH and Toxins A/B in one analytical step leading to aOf 171 GDH-positive samples, 4 were excluded (from patients on therapy or from whom duplicate samples were obtained) and 88 were determined to be true positives for toxigenic C. Stage one of these tests looks for a chemical called glutamate dehydrogenase (GDH). diff infection, but you carry the C. A recently marketed enzyme immunoassay for glutamate dehydrogenase (GDH), TechLab's C. 25: COI <16. Toxin assay will be performed. GDH-positive patients were considered infected or colonized, and those who were faecal toxin-positive were considered to be infected (i. GDH tends to catalyze the positive deamination of glutamate to produce α-KG, providing energy for the TCA cycle in the brain. 1. The Singulex Clarity C. Ce inseamna acest lucru?Methods. C. difficile toxin B gene (tcdB) by polymerase chain reaction (PCR). Eight samples (2. 3% of the total samples in GDH. If the CDAB results are positive, laboratory diagnosis of CDI can be made. If you are GDH positive you will, if available, be nursed in a single roomAnother 71 (16. Therefore, we believe the toxin component of the C. Clostridioides difficile infection (CDI) is a major cause of illness and death worldwide (1,2). Glutamate dehydrogenase (GDH) is a hexameric enzyme that catalyzes the reversible conversion of glutamate to α-ketoglutarate and ammonia while reducing NAD(P) + to NAD(P)H (Figure 1) []. In addition, B-GUS- and GDH-positive bacteria cooperatively converted PhIP-G to PhIP-M1. Therefore, enrichment cultures or additional real-time PCR tests are recommended for GDH-positive, culture-negative samples. difficile PCR (Cepheid GeneXpert) from December 2016 to October 2020 (n = 368) at a tertiary. Cultivarea este metoda cu sensibilitate cea mai ridicată și este importantă pentr u evaluari epidemiologice. The GDH test has high sensitivity and. GDH POSITIVE Patient Information Leaflet Infection Prevention Team . e. Analytical sensitivity: 0. Detection of a GDH-positive EIA-toxin-positive result in a subsequent stool. In this study, two chemiluminescent immunoassays (CLIAs), one for GDH and the other for the toxins A. d Twelve cases were GDH negative. ABSTRACT The diagnosis of Clostridium difficile infection continues to be a challenge for many clinical microbiology. Of 38 samples, 27 revealed a positive result for GDH and free toxins A/B in the stool, and 11 samples only for the presence of GDH. In this study, two chemiluminescent immunoassays (CLIAs), one for GDH and the other for the toxins A. 효소면역법 (enzyme immunoassay, EIA)으로 C. Isolates were subcultured to BHI and grown for 72h then tested by tissue culture for the presence of toxin B. difficile culture-negative result (6, 9). difficile isolates were available for molecular analysis; seventeen belonged to PCR-ribotype 001 (85 %) whereas the. In this study, we evaluated these three immunoassays for. Of 150 PCR-positive specimens, 52 (34. difficile in 47 out of the 54 (87. difficile iar boala actuală are o altă etiologie Notă: Și în cazul diagnosticării ICD din prima etapă se poate efectua cultură din proba de materii fecale, dar nu în scop diagnostic, ci pentru a avea disponibilă bacteria înThose specimens with discrepant results (GDH positive/toxin negative or GDH negative/toxin positive) would reflex to Xpert C. Twenty-eight results were discordant between the two methods: 27 stool samples were positive by Xpert PCR and negative by GDH-CYT, and 1 stool sample was positive by GDH-CYT and negative by Xpert PCR. There is insufficient evidence to recommend against repeat testing of the sample using NAAT after an initial negative result due to a lack of evidence. The aforementioned reaction also yields ammonia, which in eukaryotes is canonically processed as a substrate in the urea cycle. These EIA tests were initially not very sensitive and therefore were often used as an initial screening tool, paired with other tests to confirm positive results. difficile-specific antibodies indicating prior C. GDH and toxin positive: Toxigenic . Where there is a negative GDH but a positive toxin test the sample should be retested, as this is an invalid result. The recombinant protein His 6-TF-TrGDH was affinity purified with nickel-nitrilotriacetic acid. lépés: toxin vizsgálat Értékelés c. 1. If toxin (either A or B or both) and GDH are present, the specimen is considered positive. GDHs are members of a superfamily of. diff infections can sometimes lead to more serious problems like sepsis. diff lives in the gut of around 3% of the. difficile test (Cepheid, Sunnyvale, CA, USA) were used to ascertain the toxin/toxigenic status of patients. Compared with NAAT, the GDH test had a sensitivity of 87. 2%) were positive by GDH and PCR only and were deemed negative for purposes of calculating performance characteristics. . GDH is considered a screening method because it is expressed by both the toxigenic and nontoxigenic strains. The glutamate dehydrogenase (GDH) catalyses the reversible conversion of glutamate into α-ketoglutarate, which initiates amino acid transamination during cheese ripening. However, the clinical significance remains unclear in cases that demonstrate a. for 10 days + intracolonic vancomycin 500 mg in 100 ml of normal. Antigen detection for C. Positive samples with GDH-EIA test and test for toxin A/B-EIA (two-step algorithm), according to the age group of the patients (n=511) are displayed in Fig. Thirty‐two (16. Beginning today, February 24, 2015, the University of Iowa Hospitals and Clinics Microbiology laboratory will perform C. The two-step procedure consisted of GDH-toxin A/B EIA (Enzyme immunoassay targeting enterotoxin A and Cytotoxin B), followed by PCR detecting toxigenic C. PCR-RFLP analysis was carried out by digesting the secondary PCR products of the nested-PCR of bg and gdh genes. The clinical spectrum of C. However, current assays based on GDH activity or GDH. 0001). Clostridium difficile - GDH - metode și materiale folosite. The percentage of patients with GDH-positive express test results, but negative results for toxins, was 16. dif ficile DNA and for preliminary. A decision tree was constructed to compare two CDI diagnostic approaches (Microsoft Excel ® 2016) from the Japan government payer’s perspective: (1) one-step pathway with NAAT alone; (2) two-step algorithm with GDH/toxin followed by NAAT (stool samples were first tested with GDH and toxin; where GDH. The infection can sometimes be treated at home, or you might need to go into hospital. The presence of antigen may not correlate with disease. Egészséges embereknél rendszerint nem jelentkeznek panaszok, ha megfertőződnek ezzel a baktériummal. , Dong Joon Song, M. The GDH Enzymes. The corrected sensitivity and specificity of the PCR assay. 9–99. Positive GDH assay results must. DISCUSSION: Using GDH antigen as the screening and toxin A and B as confirmatory test for C difficile, 85% of specimens were reported negative or positive within 4 h. Toxin assay will be performed. Briefly centrifuge all small vials prior to opening. If the GDH is positive but the toxin EIA is negative, adjudication with NAAT is beneficial. diffidile GDH is a rapid qualitative enzyme immunoassay screening test. , 24 (12%) were positive for CDI using a GDH test, a PCR-based test, and a toxin-based ELISA, 22 (19%) were positive using GDH- and PCR-based tests, 7 (33%) were positive using a GDH-based test, and 1 was positive according to a GDH test and toxin-based ELISA. Rapid and Reliable Diagnostic Algorithm for Detection of Clostridium difficile. e. difficile DIFF CHEK-60 (TL-GDH) in combination with the Triage C. difficile assay but negative by reference toxigenic culture shows that 7 of 13 specimens appear to be true-positive specimens, given the positive GDH, EIA, and/or CCCN results (Table (Table2). 8%) were immunocompromised. A Clostridiodies difficile (korábban: Clostridium difficile, sokszor rövidítve: C. What does GDH positive-toxin negative mean? As described above, the first test of the sample will look for the chemical GDH, if the. Glucose dehydrogenase (GDH) is a NAD(P)+ dependent oxidoreductase, which is useful in glucose determination kits, glucose biosensors, cofactor regeneration, and biofuel cells. GDH? (Glutamate Dehydrogenase) Patient Information Leaflet If you require a translation or alternative format of this leaflet please call Infection Prevention & Control 01296 315337 The fact that you are GDH positive will be recorded on your electronic patient record. A true positive (TP) was defined as positivity by CCNA or positivity by LAMP plus another test (GDH, CDT, or the Premier C. The patient has nontoxigenic C. However, the clinical significance remains unclear in cases that demonstrate a positive. The 13. Simultaneous Detection of Clostridioides difficile Glutamate Dehydrogenase and Toxin A/B: Comparison of the C. Among 356 GDH positive/toxin negative patients, cultures were performed in 220 cases and toxigenic C. The highest GDH specific activity is found in the liver [62,88,89], where the However, a more specific test to detect free toxins is required to confirm the diagnosis for glutamate dehydrogenase (GDH)-positive and toxin-negative samples. orally for 10–14 days (if oral therapy is possible) Metronidazole 500 mg t. The GDH test has high sensitivity and. At bioMérieux, the testing of the 36 GDH-positive CCNA-negative samples was completed, as well as additional testing for samples that gave discordant results between CCNA and. 7) and 0. The most likely explanation for this discrepancy is cross-reactivity to toxins formed by other clostridial species, such as C. Clostridium difficile infection (CDI) is a leading cause of healthcare-associated infections, accounting for significant disease burden and mortality. 2017. difficile were initiated versus 4/28 (14. difficile infection that keeps coming back. Samples with equivocal or negative CDAB results should be referred for further testing, such as molecular detection of toxin genes, toxigenic culture (TC) or cell. The expression of GDH was determined by qPCR,. • PCR analysis –DNA was extracted from broth cultures using the QIAamp Mini Kit (Qiagen, Valencia, CA). 006. GDH detects toxigenic as well as non-toxigenic strains and while it has been recommended as a screening tool in combination with other confirmative tests for GDH-positive samples [13, 14], its sensitivity was reported to be less than optimal [6, 15]. difficile (GDH), dar un rezultat negativ al toxinei C. This study included all GDH-positive and four GDH-negative samples from August 1st to October 22th 2013 (defined as the first period), and all samples submitted from May 20th to June 5th 2014 (defined as the second period), without knowledge of the patients' clinical information. The isolate then tested positive for GDH and toxins A and B; however, the GeneXpert C. The combination diagram showed that the green and the blue signal did not coincide, indicating that Sc-GDH was not expressed in the nucleus ( Figures 3 , ,4 4 ). Four (5%) samples were GDH-positive by theLiaison® test alone. Results: Thirty-six (42%) samples were GDH negative and toxin A/B negative by both tests. 2. Some other organisms that live in the human intestine produce an immunologically related GDH, so optimal performance requires GDH testing performed with immunoassays that have highly specific antibodies for GDH from C. Though none of the assays could detect. Firstly all diarrhoeal stool samples are tested using a sensitive screening test – GDH (glutamate dehydrogenase). All Contacts. A Clostridium difficile fertőzés többnyire csak akkor okoz gondot, ha a bélflóra nem ép vagy egyensúlya felborult, például anitbiotikum hosszas szedését követően, illetve beteg, sérült, gyulladt. Show abstract. A subgroup of these samples could neutralize both toxins from RT027. dacă este pozitiv se confirmă ICD dacă este negativ este foarte probabilă colonizarea cu C. The detection of GDH does not distinguish between toxigenic and nontoxigenic strains. References. Glutamate dehydrogenase (GDH) antigen is an enzyme that is produced by C. Buna seara, Am fost diagnosticata cu clostridium difficile (toxina A pozitiva) si am luat tratament Metronidazol timp de 10 zile. In the two-round workflow for the diagnosis of CDI by applying GDH and CD toxin A/B testing, when GDH and CD toxin A/B were both negative or both positive, the use of VIDA, RIDA, and QCC for first-round testing in a two-round workflow eliminated the requirement for second-round testing in 71. If this is found in your sample, this means that you have C. 4%), then C. 클로스트리디오이데스 디피실 장염(Clostridioides difficile Infection, CDI)이란 항생제를 투여받는 환자의 장관에 정상 세균총 (colonic flora) 구성이 변화하면서 C. difficile toxin A and B enzyme immunoassay [P-EIA]). Diff Quik Chek Complete assay, which tests for the presence of both glutamate dehydrogenase (GDH) and C. Și nu știu care sunt riscurile pt făt atât cauzate de bacterie cat și de tratament. Read more. Glutamate dehydrogenase (GDH) antigen assays have been found to be good screening tests for C. No. All G. Detection of C. Results indicate that EIAs provide a rapid screening assay for the laboratory diagnosis of CDI but, in GDH-positive and toxins-negative samples, EIA should be always followed by. 5-100%, and NPV, reported to be 94. Data from 113 inpatients aged > 2 years whose stool samples were GDH. Since this sample was determined to be negative by TC, it was designated as a toxin A/B false-positive result. Diff Quik Chek Complete D-EIA provides a rapid and reproducible first-line screening assay for laboratory diagnosis of C. diff is also called C. If the GDH is negative, CDI can effectively be ruled out due to a greater than 95% sensitivity of the GDH assay. Patients who test. Glutamate dehydrogenase (GDH) is a homohexameric enzyme that catalyzes the reversible oxidative deamination of l -glutamate to 2-oxoglutarate. The GDH-EIA-CCCN procedure required, on average, 2 days to complete testing on GDH-positive results, while testing by the Xpert C. 9%) were diagnosed on the basis of a GDH/toxin-positive EIA (‘toxin-positive group’), whereas 125 episodes (54. Valori normale : negativ/nereactiv. 5 μmol, Lyophilized) 1 vial 4. suis identification using the gdh gene is challenging. A C. According to our validation studies. We calculated sensitivity, specificity, positive and negative predictive values as measures of test performance, as well as local prevalence. 1%) giving a true positive result. difficile toxina A&B. Further, in both standard. Therefore, the currently used multi-step algorithm is a reasonable solution. Symptom duration was significantly shorter in patients with toxin-negative rather than toxin-positive stool specimens, despite the lack of CDAD drug treatment in all but one of the 29 toxin. difficile. A therapy known as bezlotoxumab (Zinplava) is a human antibody against C. No toxin EIA-positive case was found among GDH-negative samples, and 60. difficile 균이 증식하고, 동시에 독소를 분비하여 발생하는 항생제 관련 설사병 (antibiotic-associated diarrhea, AAD. Clostridium difficile, an anaerobic spore-forming Gram-positive bacillus found commonly in the environment, was recognized since 1978 as an important cause of nosocomial diarrhea in hospitalized patients receiving antibiotics for a variety of infections, and was often difficult to diagnose and treat. Reflex testing is performed at an additional charge. Patients. bioMérieux's Complete C. C. A Clostridium difficile-fertőzés kezelése. Of 200 GDH-positive samples, 71 were positive by the Tox A/B II ELISA, 88 were positive by the two-step method, 93 were positive by PCR, and 96 were positive by the GDH antigen assay only. View. Results: In the CR, the most commonly used test in the diagnosis of CDI is the C. difficile toxin A/B immunoassay, human stool specimens from patients with diarrhoea (n = 1085) were classified as either GDH positive/toxin negative, or GDH positive/toxin positive. A large conformational difference between open and closed GDH system. difficile detected or 2) false positive GDH. Enyhe fertőzöttség esetén előfordul, hogy további kezelésre nincs szükség. 1. Therefore, a combination of EIA with cell-culture cytotoxin assay targeting glutamate dehydrogenase (GDH) is recommended to achieve the highest diagnostic accuracy. GDH from animals, but not other kingdoms [ 2 ], is allosterically regulated. GDH detection by both commercial tests showed high sensitivity (100%) and specificity (92. difficile by Cepheid)From the swab samples obtained in Laguna, direct detection of the S. 2%; one sample yielded one toxigenic and one nontoxigenic strain, another had two distinct toxigenic strains isolated), while 10 (2. In this study, the performance of the Clarity assay was compared to that of a multistep algorithm using an enzyme immunoassay (EIA) for detection of glutamate dehydrogenase (GDH). GDH (glutamate dehydrogenase) is an enzyme present in C. Diff Quik Chek Complete D-EIA provides a rapid and reproducible first-line screening assay for laboratory diagnosis of C. , Hee Jae Huh, M. It used to be called Clostridium difficile. GDH had a sensitivity of 100% with CTN as the reference method but a marginal positive predictive value in our hands of 53%. The authors reported intense astrocytic GDH. C. 3%) were culture negative. A positive toxin production confirms the diagnosis of Clostridium difficile infection (Appendix 8 and 9). As most of the rapid malaria diagnostic tests are based on the detection of HRP2 protein in the blood, we attempted to use Glutamate. d Twelve cases. Limite si interferente. Result must be included in mandatory reporting; • If GDH EIA (or NAAT) positive, and toxin EIA negative, then C. Introducing a random-access screening test resulted in. Of the 88, 67 (76. When positive by itself and compared to clinical diagnosis of C. 1%) were positive by the two-step method and 86 (97. The specificity was 93. difficile strain is present. These studies have focused primarily on those specimens that are GDH positive but EIA negative, due to the low sensitivity of the EIA component of the assays. 8%. will look for the presence of GDH. DIFF Quik Chek Complete® test (Alere) for the detection of GDH. diff Chek-60 glutamate GDH assay (Techlab, Blacksburg, VA, USA), the DoH recommended Cell Cytotoxicity Neutralisation Assay and the Xpert C. 2b). ImmunoCard C. The patient is an asymptomatic carrier of toxigenic C. diff) a Clostridiodies nembe tartozó Gram-pozitív baktérium, az álhártyás vastagbélgyulladás leggyakoribb okozója. difficile PCR assay. If GDH negative and toxin positive, always a false positive (very rare). If the result is GDH positive, a second test is performed to look for toxins that are produced when C. Prezent în flora microbiană normală a intestinului subțire, C. 0:In the post-intervention period, 5. This study aimed to implement a toxigenic culture as an optional third diagnostic step for glutamate dehydrogenase (GDH)-positive and toxin A/B-negative diarrheal stool samples into a diagnostic algorithm for Clostridioides (Clostridium) difficile infection (CDI), and to characterise C. i. The specificity was 93. difficile. Six (7%) samples only were GDH positive and toxin positive by the Liaison® test alone. With this three-step approach, results of c. Newer rapid tests for CDI may reduce this. In our hands, the toxin A/B RDT is even more sensitive than the EIA (7. Other studies evaluating GDH specificity in commercial tests reported samples with a false-positive GDH result due to a discrepancy with the C. The expression of GDH was determined by qPCR,. Clostridium difficile - toxina A și B Factorii principali de virulenţă sunt toxina A & B, care se leagă de suprafaţa celulelor epiteliale intestinale şi pătrund în celulă prin endocitoză, după care atacă. duodenalis was detected in three. PCR Test (-) No toxigenic CDI present with positive GDH test due to one of 2 possibilities: 1) Non-toxigenic C. This approach provides confirmatory results for >90% of specimens submitted for testing. An ELISA for C. 6%) dogs were positive for A/B toxins using the enzyme immunoassay kit and 18 (15. Meta-analysis of published evidence supports the use of testing algorithms that use NAAT alone or in combination with GDH or GDH plus toxin EIA to detect the presence of C. Twenty (23%) samples were GDH positive and toxin A/B positive by both tests. Antigen detection for C. g. difficile, de aceea testul nu poate face diferenţierea între tulpinele toxigene şi tulpinile non-toxigene de C. Ce inseamna acest lucru? Hospital databases were used to collect information on glutamate dehydrogenase (GDH)-positive, toxin-negative inpatients (February–April 2015). Only 25% of the isolates were GDH positive with NAD+ as. Background: A multistep algorithm using GDH antigen plus toxin with a reflex PCR is an acceptable method for detecting CDI. Twelve samples (3. Two out of three false-negative in-house PCR results retested positive. One GDH-negative but toxin A/B-positive sample was identified by both QCC and RC. Analytical sensitivity: 0. diff. d. difficile in adults. To our best knowledge, this is the first study investigating the prevalence and course of anti-GDH antibodies. These GDH-positive but toxin-negative patients represent the proportion of cases in which diagnosis and treatment requirements are unclear. Xpert C. Overall performance of a GDH-based algorithm depends on the secondary tests used to follow up a positive GDH result, and turnaround time may. GDH antigén pozitív, A/B toxin negatív: toxin ugyan nem mutatható ki, de a GDH enzim pozitivitása jelzi a C. In contrast to previous reports, GDH-positive specimens were retested by a rapid toxin A/B test instead of time-consuming and labor-intensive CCNA (). The interpretation of a positive GDH and negative toxin assay is difficult. difficile excretors –Event Requests. difficile. D. The CDI testing algorithm consists of an initial screening step using a Premier GDH EIA (Meridian Bioscience, Cincinnati, Ohio), followed by a NAAT (Cepheid, Xpert™ C. difficile. Recent work has suggested that GDH sensitiv…The pad carries immobilized polyclonal anti-GDH antibodies at the TEST reaction port and Goat anti-mouse antibodies at the CONTROL reaction port. difficile toxins (conditioned media) produced by RT027 (26%). iv. It is an anaerobic, spore-forming, Gram-positive rod. The agreement between the GDH-CYT algorithm and the Xpert PCR was 94. The Centers for Disease Control and Prevention (CDC) classifies CDI as an urgent public health threat (). GDH EIA assays possess a sensitivity of 85%–95% and a specificity of 89%–99% [32, 33]. Furthermore, this finding implies that, among cases that are initially GDH positive and toxin negative by fecal testing, many toxin-positive CDI cases may be missed . 10. difficile glutamate dehydrogenase (GDH)-immunoassay followed by a toxin-immunoassay in positive cases is widely used. difficle GDH antibodies, lmmunoCord C. 6%) patients with a positive NAAT and GDH test and a negative toxin A&B EIA, no antibiotics against C. Quinn et al 14 investigated 174 stool specimens and found that 133 (76. The mariPOC GDH test reported five low-positive results for which true positivity could not be verified by other. 8 Cases were denoted healthcare facility-associated, community-associated or indeterminate using standard surveillance definitions. The staining intensity of GDH-positive samples ranged from light yellow to tan to sepia and was mainly located in the. difficile GDH is performed first, and GDH-positive specimens are tested further for toxin production by ELISA [21,22]. To date,15 genes have been found to be associated with the pathogenesis of CHI. difficile. difficile ranged from 11% to 17%, based on percent positive results with the reference standard, and therefore, predictive values should be interpreted accordingly. 3%) patients who were NAAT, GDH and toxin A&B EIA positive. Background: In the medical laboratory, a step-by-step workflow for Clostridioides difficile infection (CDI) detection using glutamate dehydrogenase (GDH) and toxin A/B assays for initial screening, along with a nucleic acid amplification test (NAAT), has been recommended recently. 1). The most likely explanation for this discrepancy is cross-reactivity to toxins formed by other clostridial species, such as C. Overall agreement is high, with 97 % and 98 % for GDH and toxin A/B tests respectively. The VIDAS GDH assay was found to be useful as a first step in the two- or three-step algorithm for C. Of the remaining low number of specimens that are positive by GDH or NAAT. If the PCR test is positive, then the result is reported as positive for C. Assuming the patients who were GDH positive and toxin equivocal/negative as possible CDI, the incidence was 0. The effectiveness of GDH as a diagnostic marker is well-documented. ) (Quik Chek). The agreement between the GDH-CYT algorithm and the Xpert PCR was 94. Cases of positive CD PCR, positive GDH, and negative toxin were listed as unclear regarding interpretation. has changed. A C. Cytotoxicity assay is considered as the reference method for detecting free toxins (mainly toxin B) in stools. The use of the PCR in discordant cases can identify those patients who are colonized from those patients who have nontoxogenic strains of C. The performance of the two-step protocol was compared with toxin detection by the Meridian Premier EIA kit in.