scholarly journals Reliability of Cobas Amplicor PCR test in detection of Mycobacterium tuberculosis in respiratory and nonorespiratory specimens

2009 ◽  
Vol 66 (12) ◽  
pp. 992-997
Author(s):  
Zorica Lepsanovic ◽  
Dejana Savic ◽  
Branka Tomanovic
Keyword(s):  
Mycobacterium Tuberculosis ◽  
High Sensitivity ◽  
High Specificity ◽  
Diagnostic Methods ◽  
Nucleic Acid Amplification ◽  
Culture Methods ◽  
Predictive Values ◽  
Polymerase Chain ◽  
Low Sensitivity ◽  
Sensitivity Specificity

Background/Aim. Traditional methods for detection of mycobacteria, such as microscopic examination for the presence of acid-fast bacilli and isolation of the organism by culture, have either a low sensitivity and/or specificity, or take weeks before a definite result is available. Molecular methods, especially those based on nucleic acid amplification, are rapid diagnostic methods which combine high sensitivity and high specificity. The aim of this study was to determine the usefulness of the Cobas Amplicor Mycobacterium tuberculosis polymerase chain reaction (CAPCR) assay in detecting the tuberculosis cause in respiratory and nonrespiratory specimens (compared to culture). Methods. Specimens were decontaminated by the N-acetyl-L-cystein- NaOH method. A 500 ?L aliquot of the processed specimen were used for inoculation of L?wenstein-Jensen (L-J) slants, a drop for acid-fast staining, and 100 ?L for PCR. The Cobas Amplicor PCR was performed according to the manufacturer's instructions. Results. A total of 110 respiratory and 355 nonrespiratory specimens were investigated. After resolving discrepancies by reviewing medical history, overall sensitivity, specificity, and positive and negative predictive values for CA-PCR assay compared to culture, were 83%, 100%, 100%, and 96.8%, respectively. In comparison, they were 50%, 99.7%, 87.5%, and 98%, respectively, for the nonrespiratory specimens. The inhibition rate was 2.8% for respiratory, and 7.6% for nonrespiratory specimens. Conclusion. CA-PCR is a reliable assay that enables specialists to start treatment promptly on a positive test result. Lower value for specificity in a group of nonrespiratory specimens is a consequence of an extremely small number of mycobacteria in some of them.

Validity of hearTest Smartphone-Based Audiometry for Hearing Screening in Workers Exposed to Noise

2020 ◽  
Author(s):  
Luma Cordeiro Rodrigues ◽  
Silvia Ferrite ◽  
Ana Paula Corona
Keyword(s):  
Hearing Loss ◽  
High Specificity ◽  
Hearing Screening ◽  
Youden Index ◽  
Hearing Level ◽  
Predictive Values ◽  
Auditory Thresholds ◽  
The Mean ◽  
Low Sensitivity ◽  
Sensitivity Specificity

Abstract Purpose This article investigates the validity of a smartphone-based audiometry for hearing screening to identify hearing loss in workers exposed to noise. Research Design This is a validation study comparing hearing screening with the hearTest to conventional audiometry. The study population included all workers who attended the Brazilian Social Service of Industry to undergo periodic examinations. Sensitivity, specificity, the Youden index, and positive (PPV) and negative predictive values (NPV) for hearing screening obtained by the hearTest were estimated according to three definitions of hearing loss: any threshold greater than 25 dB hearing level (HL), the mean auditory thresholds for 0.5, 1, 2, and 4 kHz greater than 25 dB HL, and the mean thresholds for 3, 4, and 6 kHz greater than 25 dB HL. Note that 95% confidence intervals were calculated for all measurements. Results A total of 232 workers participated in the study. Hearing screening with the hearTest presented good sensitivity (93.8%), specificity (83.9%), and Youden index (77.7%) values, a NPV (97.2%), and a low PPV (69.0%) for the identification of hearing loss defined as any auditory threshold greater than 25 dB HL. For the other definitions of hearing loss, we observed high specificity, PPV and NPV, as well as low sensitivity and Youden index. Conclusion The hearTest is an accurate hearing screening tool to identify hearing loss in workers exposed to noise, including those with noise-induced hearing loss, although it does not replace conventional audiometry.

scholarly journals Development of an in-house loop-mediated isothermal amplification (LAMP) assay for detection of Mycobacterium tuberculosis and evaluation in sputum samples of Nepalese patients

2008 ◽  
Vol 57 (4) ◽  
pp. 439-443 ◽  
Author(s):  
Basu Dev Pandey ◽  
Ajay Poudel ◽  
Tomoko Yoda ◽  
Aki Tamaru ◽  
Naozumi Oda ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Lamp Assay ◽  
High Sensitivity ◽  
Isothermal Amplification ◽  
Nucleic Acid Amplification ◽  
Lamp Method ◽  
Rrna Gene ◽  
Predictive Values ◽  
Loop Mediated Isothermal Amplification ◽  
System A

A number of nucleic acid amplification assays (NAAs) have been employed to detect tubercle bacilli in clinical specimens for tuberculosis (TB) diagnosis. Among these, loop-mediated isothermal amplification (LAMP) is an NAA possessing superior isothermal reaction characteristics. In the present study, a set of six specific primers targeting the Mycobacterium tuberculosis 16S rRNA gene with high sensitivity was selected and a LAMP system (MTB-LAMP) was developed. Using this system, a total of 200 sputum samples from Nepalese patients were investigated. The sensitivity of MTB-LAMP in culture-positive samples was 100 % (96/96), and the specificity in culture-negative samples was 94.2 % (98/104, 95 % confidence interval 90.5–97.9 %). The positive and negative predictive values of MTB-LAMP were 94.1 and 100 %, respectively. These results indicate that this MTB-LAMP method may prove to be a powerful tool for the early diagnosis of TB.

scholarly journals Evaluation of the Abbott LCx Mycobacterium tuberculosis Assay for Direct Detection of Mycobacterium tuberculosis Complex in Human Samples

1999 ◽  
Vol 37 (1) ◽  
pp. 229-232 ◽  
Author(s):  
Maria Grazia Garrino ◽  
Youri Glupczynski ◽  
Josiane Degraux ◽  
Henri Nizet ◽  
Michel Delmée
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Direct Detection ◽  
Clinical Samples ◽  
Culture Methods ◽  
Predictive Values ◽  
Direct Microscopy ◽  
Standard Culture ◽  
Small Gain ◽  
Clinical Interest ◽  
Sensitivity Specificity

Seven hundred thirty-seven clinical samples from 460 patients were processed for direct detection of Mycobacterium tuberculosis complex by a semiautomated ligase chain reaction commercial assay, the LCx Mycobacterium tuberculosis Assay (LCx assay) from Abbott Laboratories. Results were compared to those of direct microscopy and standard microbiological culture. Of 26 patients (5.7%) with a culture positive for M. tuberculosis, 22 (84.6%) were found positive by the LCx assay. The sensitivity of the LCx assay was 98% for smear-positive samples and 27% for smear-negative samples. With an overall culture positivity rate forM. tuberculosis of 8.3% (61 of 737 samples) and after resolution of discrepant results according to clinical data, the sensitivity, specificity, and positive and negative predictive values of the LCx assay were 78, 100, 95, and 98%, respectively, compared to 85, 100, 100, and 98%, respectively, for culture and 67, 99, 87, and 97%, respectively, for acid-fast staining. In conclusion, the LCx assay proved satisfactory and appears to be an easy-to-use 1-day test which must be used with standard culture methods but can considerably reduce diagnosis time versus culture. However, its clinical interest appears to be limited in our population with low mycobacterial prevalence because of its cost considering the small gain in sensitivity versus direct microscopy.

scholarly journals COMPARISON OF A DNA BASED PCR APPROACH WITH CONVENTIONAL METHODS FOR THE DETECTION OF MYCOBACTERIUM TUBERCULOSIS IN MOROCCO

2012 ◽  
Vol 4 (1) ◽  
pp. e2012049 ◽  
Author(s):  
Fathiah Zakham ◽  
Oufae Lahlou ◽  
Mohammed Akrim ◽  
Nada Bouklata ◽  
Sanae Jaouhari ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Insertion Sequence ◽  
Clinical Manifestations ◽  
Public Health Problem ◽  
High Specificity ◽  
Major Public Health Problem ◽  
Predictive Values ◽  
Polymerase Chain ◽  
Pcr Techniques ◽  
Potential Tool

Background: Worldwide, tuberculosis (TB) is a major public health problem and the rapid diagnosis and appropriate chemotherapy become the first priority and a serious challenge to improve TB treatment.In the objective of early TB diagnosis and rapid detection of Mycobacterium tuberculosis (MTB) in the clinical specimens, the utility of the Polymerase Chain Reaction (PCR) using the Insertion Sequence 6110 (IS6110) as target was compared to conventional methods.Methods: Out of 305 patients with different clinical manifestations: suspected, new, drug relapse, drug failure and chronic cases were enrolled in this study and tested by mycobacteriological and PCR techniques for the investigation about the tubercle bacilli.Results: The results of the in house IS6110 PCR showed a good sensitivity (92, 42%) and high specificity (98%), the positive and negative predictive values were 96.4 % and 95.3 % respectively.Conclusion: This study showed clearly that the PCR testing using the IS6110 in the routine analysis is a potential tool for the rapid TB diagnosis, especially for critical cases and would be of great interest to help the clinician in the misdiagnosed critical cases by the traditional radiology.

scholarly journals Evaluation of the COBAS AMPLICOR MTB test for the detection of Mycobacterium tuberculosis complex

2004 ◽  
Vol 10 (3) ◽  
pp. 329-335
Author(s):  
K. K. Abu Amero ◽  
M. A. Halablab
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mycobacterium Tuberculosis Complex ◽  
Tuberculosis Complex ◽  
False Negatives ◽  
Predictive Values ◽  
Lowenstein Jensen ◽  
Polymerase Chain ◽  
Sensitivity Specificity ◽  
Culture Positive ◽  
Positive Results

Wevaluated the COBAS AMPLICOR polymerase chain reaction [PCR] based test for the detection of Mycobacterium tuberculosis complex in 866 respiratory and non-respiratory samples. Acid-fast staining and culture on Lowenstein-Jensen medium were also performed on all samples. Of the 866 samples tested, 87 [10.0%] were PCR-positive compared to 94 [10.9%] culture positive. There were no false positive results but 7 PCR-negative, culture-positive samples were, considered false negatives after reviewing medical records of patients. A PCR inhibitory rate of 2.0% [17/866] was observed in respiratory samples only. Sensitivity, specificity, and positive and negative predictive values for this test were 92.5%, 100%, 100% and 99.1% respectively. This test is a valuable diagnostic tool for today’s mycobacteriology laboratory

scholarly journals Rapid Diagnosis of Pulmonary Tuberculosis with the LCx Mycobacterium tuberculosis Assay and Comparison with Conventional Diagnostic Techniques

1998 ◽  
Vol 36 (10) ◽  
pp. 3046-3047 ◽  
Author(s):  
Peter Rohner ◽  
Esther I. M. Jahn ◽  
Beatrice Ninet ◽  
Concetta Ionati ◽  
Rainer Weber ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Direct Detection ◽  
Diagnostic Techniques ◽  
Nucleic Acid Amplification Test ◽  
Nucleic Acid Amplification ◽  
Predictive Values ◽  
Amplification Assay ◽  
Sensitivity Specificity ◽  
Culture Positive ◽  
Respiratory Specimens

The LCx MTB amplification assay is a nucleic acid amplification test intended for the direct detection ofMycobacterium tuberculosis complex in respiratory specimens. We evaluated its performance on 2,001 consecutive respiratory specimens; 78 were culture positive for M. tuberculosis. Sensitivity, specificity, and positive and negative predictive values of this assay for all specimens compared to culture results were 88.5, 97.7, 60.5, and 99.5%, respectively. When referred to resolved clinical diagnosis of active tuberculosis, these values improved to 90.2, 98.4, 72.8, and 99.5%, respectively.

Study on Diagnostic Values of Astrocyte Elevated Gene 1 (AEG-1) and Glypican 3 (GPC-3) in Hepatocellular Carcinoma

2019 ◽  
Vol 152 (5) ◽  
pp. 647-655 ◽  
Author(s):  
Wenqing Cao ◽  
Meenal Sharma ◽  
Rami Imam ◽  
Jiangzhou Yu
Keyword(s):  
Hepatocellular Carcinoma ◽  
High Sensitivity ◽  
High Specificity ◽  
The Other ◽  
Diagnostic Potential ◽  
Dysplastic Nodules ◽  
Nontumor Tissue ◽  
Diagnostic Values ◽  
Low Sensitivity ◽  
Sensitivity Specificity

Abstract Objectives To investigate the diagnostic potential of AEG-1 and GPC-3 in hepatocellular carcinoma (HCC). Methods AEG-1 and GPC-3 immunohistochemistry were performed on HCC, adjacent nontumor tissue (ANT), and dysplastic nodules (DN). Results H score of AEG-1 or GPC-3 in HCC was significantly higher than in ANT or DN. In HCC, 92% and 54% showed AEG-1 and GPC-3 positivity, respectively. In ANT, 16.2% were AEG-1 and 7.6% GPC-3 positive. AEG-1 staining was mostly diffuse, whereas GPC-3 frequently showed focal staining. AEG-1 alone showed high sensitivity but low specificity and accuracy. GPC-3, on the other hand, showed high specificity but low sensitivity and accuracy. Combination of both stains boosted the sensitivity, specificity, and accuracy to 94.6%, 89.5%, and 90.5%, respectively, when only diffuse staining was considered as positive. Conclusions AEG-1 or GPC-3 alone seemed not an ideal marker for HCC. The combination of AEG-1 and GPC-3 might improve early diagnosis of HCC.

scholarly journals Comparison of GeneXpert MTB to Mycobacterium tuberculosis culture in children with tuberculosis

2019 ◽  
Vol 59 (3) ◽  
pp. 113-8
Author(s):  
Betty Agustina ◽  
Cissy Kartasasmita ◽  
Dany Hilmanto
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Tuberculin Test ◽  
Female Gender ◽  
Positive Tuberculin Skin Test ◽  
Nucleic Acid Amplification ◽  
Kappa Index ◽  
Factors Associated ◽  
Long Time ◽  
Low Sensitivity ◽  
Sensitivity Specificity

Background Diagnosing tuberculosis (TB) in children is difficult. Typical methods take a long time to achieve results, or have a low sensitivity. GeneXpert is a nucleic acid amplification test used to identify Mycobacterium tuberculosis bacteria (MTB) in only 2 hours. Objective To compare the sensitivity and specificity of GeneXpert MTB to MTB culture in children with TB, and to assess factors associated with GeneXpert MTB test in predicting which children were likely to have positive results. Methods This descriptive, analytical study was done in children with suspected TB, aged 1 month to 18 years in Hasan Sadikin Hospital, Bandung, West Java, from January 2016 to December 2017. The data were taken from the medical records and included age, gender, nutritional status, symptoms of TB, chest x-ray, and tuberculin test results. The GeneXpert MTB test was compared to cultures from the same patient, with regards to sensitivity, specificity, and agreement using Kappa index. We analyzed factors associated to GeneXpert MTB test using logistic regression analysis. Results From 454 inpatients and 1,750 outpatients with suspected TB, there were 251 children who were tested by MTB culture and 722 children tested by GeneXpert MTB. Of the 70 cases who met the inclusion criteria and underwent both tests, factors associated with positive GeneXpert MTB results were age 10 to 18 years, female gender, and positive tuberculin skin test (TST). The GeneXpert MTB test showed sensitivity 78.9% (95%CI 56.7 to 91.5) and specificity 86.3% (95%CI 74.3 to 93.2), with accuracy of 84.3% (95%CI 74 to 91), and agreement value of ƙ=0.62 (95%CI 41.6 to 82.7). Conclusion Specificity of GeneXpert MTB is higher than its sensitivity compared to TB cultures in children. The tests were in good agreement. Age 10 to 18 years had the strongest association with positive GeneXpert MTB results.

scholarly journals Comparative Evaluation of Initial and New Versions of the Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test for Direct Detection of Mycobacterium tuberculosis in Respiratory and Nonrespiratory Specimens

1998 ◽  
Vol 36 (3) ◽  
pp. 684-689 ◽  
Author(s):  
Fredy Gamboa ◽  
Gregorio Fernandez ◽  
Eduardo Padilla ◽  
José M. Manterola ◽  
Joan Lonca ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Direct Detection ◽  
Turnaround Time ◽  
Nucleic Acid Amplification ◽  
Clinical Samples ◽  
Direct Test ◽  
Predictive Values ◽  
Staining Methods ◽  
Sensitivity Specificity ◽  
Respiratory Specimens

We evaluated the initial version of the Amplified Mycobacterium Tuberculosis Direct Test (Gen-Probe) (AMTDT 1) and the new version of AMTDT (AMTDT 2) for the detection of Mycobacterium tuberculosis directly from respiratory and nonrespiratory samples and compared the results with those of culture and staining methods. The assays were applied to 410 respiratory and 272 nonrespiratory samples collected from 515 patients. The combination of the culture results and clinical diagnosis was considered to be the “gold standard.” Ninety-five respiratory specimens were collected from 67 patients with a diagnosis of pulmonary tuberculosis (TB) and 68 nonrespiratory specimens were collected from 61 patients with a diagnosis of extrapulmonary TB. With respiratory specimens, the sensitivity, specificity, and positive and negative predictive values were 83, 100, 100, and 96%, respectively, for AMTDT 1 and 94.7, 100, 100, and 98.4%, respectively, for AMTDT 2. With nonrespiratory specimens, the sensitivity, specificity, and positive and negative predictive values were 83, 100, 100, and 94%, respectively, for AMTDT 1 and 86.8, 100, 100, and 98.4%, respectively, for AMTDT 2. The overall results of AMTDT 1 and AMTDT 2 were concordant for 97% (661 of 682) of the samples. Statistically significant differences in sensitivities were found between AMTDT 1 and AMTDT 2 with respiratory specimens. It was concluded that although both nucleic acid amplification methods are rapid, sensitive, and specific for the detection of M. tuberculosis complex in all types of clinical samples, AMTDT 2 appeared to be more sensitive than AMTDT 1 when applied to smear-negative specimens. In contrast AMTDT 2 is more susceptible than AMTDT 1 to inhibitory substances in the amplification reaction. The turnaround time of AMTDT 2 is shorter (3.5 h) than that for AMTDT 1 (5 h).

scholarly journals Evaluation of HiCrome KPC Agar for the Screening of Carbapenem-Resistant Enterobacterales Colonization in the ICU Setting of a Tertiary Care Hospital

2021 ◽  
Author(s):  
Ashoka Mahapatra ◽  
K Nikitha ◽  
Sutapa Rath ◽  
Bijayini Behera ◽  
Kavita Gupta
Keyword(s):  
Tertiary Care ◽  
High Sensitivity ◽  
Care Hospital ◽  
Predictive Values ◽  
Klebsiella Pneumoniae Carbapenemase ◽  
Carbapenem Resistant ◽  
Rectal Swabs ◽  
Control And Prevention ◽  
Indian Setting ◽  
Sensitivity Specificity

Abstract Background Spread of carbapenem-resistant Enterobacterales (CRE) is a significant concern in intensive care unit (ICU) settings. Approaches to routine screening for CRE colonization in all ICU patients vary depending on institutional epidemiology and resources. The present study was aimed to evaluate the performance of HiCrome Klebsiella pneumoniae carbapenemase (KPC) agar for the detection of CRE colonization in ICU settings taking the Centers for Disease Control and Prevention (CDC) recommended method as reference. Methods Two-hundred and eighty rectal swabs (duplicate) from 140 patients were subjected to CRE detection in HiCrome KPC agar and MacConkey agar (CDC criteria). Results Using CDC method, total 41 CRE isolates were recovered comprising of 29 E scherichia coli, 11 Klebsiella, and 1 Enterobacter spp. On the other hand, 49 isolates of CRE recovered from 140 rectal swabs using HiCrome KPC agar, out of which 33 were E. coli, 15 Klebsiella, and 1 Enterobacter sp. Statistical Analysis Sensitivity, specificity, negative, and positive predictive values of CRE screening by HiCrome KPC agar were found to be 100% (91.4–100), 91.9% (84.8–95.8), 83.6% (70.9–91.4), and 100% (95.9–100), respectively, taking the CDC recommended method as reference. Conclusion HiCrome KPC agar has high sensitivity in screening CRE colonization. Further studies are needed to establish its applicability for detecting the predominant circulating carbapenemases in the Indian setting.

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