Laboratory diagnosis ofClostridium difficileinfection. An evaluation of tests for faecal toxin, glutamate dehydrogenase, lactoferrin and toxigenic culture in the diagnostic laboratory

BACKGROUND: There has been a growing interest in developing an appropriate laboratory diagnostic algorithm forClostridium difficile, mainly as a result of increases in both the number and severity of cases ofC difficileinfection in the past decade. AC difficilediagnostic algorithm is necessary because diagnostic kits, mostly for the detection of toxins A and B or glutamate dehydrogenase (GDH) antigen, are not sufficient as stand-alone assays for optimal diagnosis ofC difficileinfection. In addition, conventional reference methods forC difficiledetection (eg, toxigenic culture and cytotoxin neutralization [CTN] assays) are not routinely practiced in diagnostic laboratory settings.OBJECTIVE: To review the four-step algorithm used at Diagnostic Services of Manitoba sites for the laboratory diagnosis of toxigenicC difficile.RESULT: One year of retrospectiveC difficiledata using the proposed algorithm was reported. Of 5695 stool samples tested, 9.1% (n=517) had toxigenicC difficile. Sixty per cent (310 of 517) of toxigenicC difficilestools were detected following the first two steps of the algorithm. CTN confirmation of GDH-positive, toxin A- and B-negative assays resulted in detection of an additional 37.7% (198 of 517) of toxigenicC difficile. Culture of the third specimen, from patients who had two previous negative specimens, detected an additional 2.32% (12 of 517) of toxigenicC difficilesamples.DISCUSSION: Using GDH antigen as the screening and toxin A and B as confirmatory test forC difficile, 85% of specimens were reported negative or positive within 4 h. Without CTN confirmation for GDH antigen and toxin A and B discordant results, 37% (195 of 517) of toxigenicC difficilestools would have been missed. Following the algorithm, culture was needed for only 2.72% of all specimens submitted forC difficiletesting.CONCLUSION: The overview of the data illustrated the significance of each stage of this four-stepC difficilealgorithm and emphasized the value of using CTN assay and culture as parts of an algorithm that ensures accurate diagnosis of toxigenicC difficile.

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The Laboratory Diagnosis of HIV Infections

Canadian Journal of Infectious Diseases and Medical Microbiology ◽

10.1155/2005/515063 ◽

2005 ◽

Vol 16 (1) ◽

pp. 26-30 ◽

Cited By ~ 18

Author(s):

Margaret Fearon

Keyword(s):

Point Of Care ◽

Diagnostic Testing ◽

Clinical Information ◽

Hiv Infections ◽

Laboratory Diagnosis ◽

The United States ◽

Specific Information ◽

Antibody Testing ◽

Diagnostic Laboratory ◽

Laboratory Results

HIV diagnostic testing has come a long way since its inception in the early 1980s. Current enzyme immunoassays are sensitive enough to detect antibody as early as one to two weeks after infection. A variety of other assays are essential to confirm positive antibody screens (Western blot, polymerase chain reaction [PCR]), provide an adjunct to antibody testing (p24 antigen, PCR), or provide additional information for the clinician treating HIV-positive patients (qualitative and quantitative PCR, and genotyping). Most diagnostic laboratories have complex testing algorithms to ensure accuracy of results and optimal use of laboratory resources. The choice of assays is guided by the initial screening results and the clinical information provided by the physician; both are integral to the laboratory's ability to provide an accurate laboratory diagnosis. Laboratories should also provide specific information on specimen collection, storage and transport so that specimen integrity is not compromised, thereby preserving the accuracy of laboratory results. Point of Care tests have become increasingly popular in the United States and some places in Canada over the past several years. These tests provide rapid, on-site HIV results in a format that is relatively easy for clinic staff to perform. However, the performance of these tests requires adherence to good laboratory quality control practices, as well as the backup of a licensed diagnostic laboratory to provide confirmation and resolution of positive or indeterminate results. Laboratory quality assurance programs and the participation in HIV proficiency testing programs are essential to ensure that diagnostic laboratories provide accurate, timely and clinically relevant laboratory results.

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Experience with the Urinary Tetrasaccharide Metabolite for Pompe Disease in the Diagnostic Laboratory

Metabolites ◽

10.3390/metabo11070446 ◽

2021 ◽

Vol 11 (7) ◽

pp. 446

Author(s):

Jennifer T. Saville ◽

Maria Fuller

Keyword(s):

Pompe Disease ◽

Late Onset ◽

Reference Interval ◽

Laboratory Diagnosis ◽

Reference Intervals ◽

Confirmatory Test ◽

Diagnostic Laboratory ◽

Age Related ◽

Initial Drop ◽

Monitoring Treatment

Following clinical indications, the laboratory diagnosis of the inherited metabolic myopathy, Pompe disease (PD), typically begins with demonstrating a reduction in acid alpha-glucosidase (GAA), the enzyme required for lysosomal glycogen degradation. Although simple in concept, a major challenge is defining reference intervals, as even carriers can have reduced GAA, and pseudodeficiencies complicate interpretation. Here, we developed a mass spectrometric assay for quantification of a urinary glycogen metabolite (tetrasaccharide) and reported on its utility as a confirmatory test for PD in a diagnostic laboratory. Using two age-related reference intervals, eight returned tetrasaccharide concentrations above the calculated reference interval but did not have PD, highlighting non-specificity. However, retrospective analysis revealed elevated tetrasaccharide in seven infantile-onset (IOPD) cases and sixteen late-onset (LOPD) cases, and normal concentrations in one heterozygote. Prospective tetrasaccharide analysis in nine individuals with reduced GAA confirmed IOPD in one, LOPD in six and identified two heterozygotes. Using this metabolite as a biomarker of therapeutic response was not overly informative; although most patients showed an initial drop following therapy initiation, tetrasaccharide concentrations fluctuated considerably and remained above reference intervals in all patients. While useful as a confirmation of PD, its utility as a biomarker for monitoring treatment warrants further investigation.

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The Laboratory Diagnosis ofHaemophilus ducreyi

Canadian Journal of Infectious Diseases and Medical Microbiology ◽

10.1155/2005/851610 ◽

2005 ◽

Vol 16 (1) ◽

pp. 31-34 ◽

Cited By ~ 21

Author(s):

Michelle Alfa

Keyword(s):

Diagnostic Testing ◽

Laboratory Diagnosis ◽

Primary Method ◽

Sample Collection ◽

Culture Methods ◽

Transmitted Infection ◽

Diagnostic Laboratory ◽

Sexually Transmitted ◽

Alternative Approaches ◽

Genetic Amplification

Chancroid is a sexually transmitted infection caused byHaemophilus ducreyi. This fastidious, Gram-negative coccobacilli dies rapidly outside the human host, making diagnostic testing using culture methods difficult. This genital ulcer infection is not common in Canada and, therefore, can often be misdiagnosed. The objective of the present paper is to provide practical approaches for the diagnosis of chancroid in Canadian patients where the prevalence of this infection is low. Issues related to sample collection, sample transport and available diagnostic tests are reviewed, and several alternative approaches are outlined. Although antigen detection, serology and genetic amplification methods have all been reported forH ducreyi, none are commercially available. Culture is still the primary method available to most laboratories. However, the special media necessary for direct bedside inoculation is often not available; therefore, communication with the diagnostic laboratory and rapid specimen transport are essential when chancroid is suspected

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Evaluation of LIAISON® C. difficile glutamate dehydrogenase and LIAISON® C. difficile toxin A and B in Copan FecalSwabTM samples in a three-step algorithm for the diagnosis of Clostridium difficile infection

Microbiologia Medica ◽

10.4081/mm.2015.4953 ◽

2015 ◽

Vol 30 (1) ◽

Author(s):

Massimo Oggioni ◽

Alessandra Bielli ◽

Alice Nava ◽

Daniela Adele Pia Campisi

Keyword(s):

Clostridium Difficile ◽

Glutamate Dehydrogenase ◽

Laboratory Diagnosis ◽

Binary Toxin ◽

Common Antigen ◽

Molecular Test ◽

Toxin A ◽

Large Numbers ◽

Step Algorithm ◽

Short Time

The presumptive laboratory diagnosis of Clostridium difficile infection is achieved by the means of the detection of a common antigen (glutamate dehydrogenase, GDH) in stool, then confirming the positives either by the detection of toxins A and B or by a molecular test for the detection of pathogenicity locus, encoding for the two toxins and for the binary toxin. A fully automated chemiluminescence system for the GDH antigen (LIAISON® C. difficile GDH) and for the detection of toxins A and B (LIAISON® C. difficile Toxin A and B) (DiaSorin, Gerenzano, Italy) allows for the performance of these tests on large numbers of samples in a short time, ensuring the traceability of the data.

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The medical laboratory prosecution of Covid – 19: pathogenesis and diagnosis

International Journal of Research in Pharmaceutical Sciences ◽

10.26452/ijrps.v11ispl1.3540 ◽

2020 ◽

Vol 11 (SPL1) ◽

pp. 1089-1098

Author(s):

Sophia Thomas ◽

Akriti Jain ◽

Divya P Mohan ◽

Arzoo R Alagh ◽

Shweta Pandey ◽

...

Keyword(s):

Rna Virus ◽

Laboratory Diagnosis ◽

Therapeutic Interventions ◽

Medical Laboratory ◽

Laboratory Evaluation ◽

Structural Protein ◽

Diagnostic Laboratory ◽

Case Identification ◽

Resource Limited ◽

Hematological Manifestations

The outbreak of 19 is now a pandemic affecting population pan . It has challenged the health system at various levels such as case identification, diagnostic laboratory workup, management and treatment and the epidemiological aspects of preventive interventions. It is so because this viral infection has never ever been encountered . The is a single stranded RNA virus with a few peculiarities of structure such as spike (S). This structural protein has been attributed to of 19 infections. The transmission of 19 is by droplets and aerosol. It primarily affects lungs, and its binding sites are cellular receptor of ACE II of . The and fatalities associated to Covid-19 infection are attributed to storm. It chiefly affects lungs producing . There are other manifestations of 19 infections. The diagnosis of 19 infection is by PCR of swab and samples from trachea and bronchi. The antibody (IgM and IgG) testing too is advised but as auxiliary in support of diagnosisThe hematological manifestations and biochemistry of the blood helps in suspecting and predicting the course of 19 infection. The present review imbibes within it, the various scientific nuances of novel corona virus that introduces -19 infection and explains the characteristics of the virus, and storm, immune evasion lung injury alteration laboratory diagnosis, , parameters of significance in laboratory of viral RNA and the proposed model of laboratory evaluation of 19 infection. The review provides a model for resource limited hospital at screening and confirmation of 19 infectionswhich will simplify, augment and enable the necessary hospital services and corrective therapeutic interventions.

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Evaluation of the Use of Rectal Swabs for Laboratory Diagnosis ofClostridium difficileInfection

Journal of Clinical Microbiology ◽

10.1128/jcm.00426-18 ◽

2018 ◽

Vol 56 (7) ◽

Cited By ~ 6

Author(s):

N. Jazmati ◽

E. Kirpal ◽

E. Piepenbrock ◽

Y. Stelzer ◽

M. J. G. T. Vehreschild ◽

...

Keyword(s):

Liquid Medium ◽

Detection Rate ◽

Laboratory Diagnosis ◽

Toxin A ◽

Suitable Alternative ◽

Content Type ◽

Toxigenic Culture ◽

Rectal Swabs ◽

Stool Samples ◽

The Impact

ABSTRACTFor the diagnosis ofClostridium difficileinfection (CDI), microbiological testing is almost always accomplished through the analysis of stool specimens. We evaluated the performances of rectal swabs with liquid transport medium (FS) and nylon flocked dry swabs for the detection ofC. difficile. Additionally, the impact on the diagnostic yield of storing swabs at −80°C for up to 3 months was evaluated. Sixty clinical stool samples positive forC. difficileby PCR were used for simulating rectal swabbing. FS and dry swabs were dipped into the stool and tested by PCR directly after swabbing at 1 and 3 months after storage at −80°C. Stool and the liquid medium of FS were additionally tested by a combination of glutamate dehydrogenase antigen (GDH) testing and toxin A/B enzyme immunoassay (EIA), as well as by toxigenic culture (TC). Using dry swabs, the PCR-based detection rate ofC. difficilewas equal to the rate using stool samples (30/30 [100%]), whereas the detection rate in FS was significantly lower (25/30 [83.2%];P= 0.019). The sensitivities of FS for detectingC. difficileby PCR, TC, GDH testing, and toxin A/B EIA were 83.3%, 85.7%, 88%, and 68.9%, respectively. Storage of swabs at −80°C had no impact on the detection rate. FS cannot replace stool samples in the two-step laboratory diagnosis of CDI, as the sensitivities were too low, probably due to diluting effects of the fecal sample in the liquid medium. For simple PCR-based detection ofC. difficile, dry swabs proved to be a suitable alternative to the use of stool samples.

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Mo1958 – Toxin a and B Combined with Glutamate Dehydrogenase Immunoassays Can Save Toxigenic Culture for the Diagnosis of Clostridium Difficile Infection

Gastroenterology ◽

10.1016/s0016-5085(19)39221-2 ◽

2019 ◽

Vol 156 (6) ◽

pp. S-900-S-901

Author(s):

Daisuke Yoshimura ◽

Toshiaki Ochiai ◽

Eikichi Ihara ◽

Yoshihiro Ogawa

Keyword(s):

Clostridium Difficile ◽

Glutamate Dehydrogenase ◽

Clostridium Difficile Infection ◽

Toxin A ◽

Toxigenic Culture

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Evaluation of Two Rapid Assays for Detection ofClostridium difficile Toxin A in Stool Specimens

Journal of Clinical Microbiology ◽

10.1128/jcm.37.9.3044-3047.1999 ◽

1999 ◽

Vol 37 (9) ◽

pp. 3044-3047 ◽

Cited By ~ 27

Author(s):

Daniel P. Fedorko ◽

Howard D. Engler ◽

Elizabeth M. O’Shaughnessy ◽

Esther C. Williams ◽

Cynthia J. Reichelderfer ◽

...

Keyword(s):

Predictive Value ◽

Chart Review ◽

Laboratory Diagnosis ◽

Clinical Diagnostics ◽

Becton Dickinson ◽

Toxin A ◽

Ofclostridium Difficile ◽

Rapid Assays ◽

Toxigenic Culture ◽

Stool Specimens

Rapid laboratory diagnosis of Clostridium difficile-associated diarrhea (CDAD) is highly desirable in the setting of hospital cost containment. We tested 654 stool specimens to compare the performance of two assays for rapid detection of toxin A, the Immunocard Toxin A test (Meridian Diagnostics, Inc.) and the Culturette Brand Toxin CD enzyme immunoassay (EIA) (Becton Dickinson Microbiology Systems), with a cytotoxin assay (Cytotoxi Test; Advanced Clinical Diagnostics) and culture on cycloserine-cefoxitin-fructose agar followed by determination of the production of toxins A and B. A chart review was performed for patients whose stool specimens provided positive results on one to three of the assays. With the “gold standard” of all four assays positive or chart review evidence of CDAD, 97 (14.8%) stool specimens were positive by one or more assays and 557 (85.2%) were negative by all methods. Total agreement for all assays was 90.5% (592 of 654). The sensitivity, specificity, positive predictive value, and negative predictive value for toxigenic culture were 94.7, 98.6, 87.1, and 99.5%, respectively, for toxigenic culture; 87.7, 98.6, 86.2, and 98.8%, respectively, for the cytotoxin assay; 71.9, 99.3, 91.1, and 97.3%, respectively, for the Immunocard; and 68.4, 99.1, 88.6, and 96.9%, respectively, for the Culturette EIA. While easy to perform and highly specific, these rapid assays do not appear to be sufficient for accurate diagnosis of CDAD.

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