Sensitivity Of GeneXpert Research Articles

Utility of CBNAAT (GeneXpert MTB/RIF assay) in rapid diagnosis of extrapulmonary tuberculosis in a hepatobiliary tertiary center

Objectives Newer diagnostic techniques like cartridge-based nucleic acid amplification techniques (CB NAAT) need to be evaluated for extrapulmonary tuberculosis (EPTB), as being a paucibacillary condition, it is often underdiagnosed with conventional methods. We conducted this study to assess the utility of CB NAAT (GeneXpert MTB/RIF assay) in rapid diagnosis of extrapulmonary tuberculosis. Material and Methods Liver disease patients admitted from June 2019 to June 2020 were investigated for EPTB based on clinical and radiological suspicion. EPTB was diagnosed based on one of the following: (i) histological evidence of caseating granulomas; (ii) smear positivity for acid-fast bacilli; (iii) CB NAAT (GeneXpert MTB/RIF assay, Cepheid, USA). Results A total of 290 EPTB specimens received in the laboratory were included. The extrapulmonary samples that were received included body fluids (n = 143) which included pleural fluid, ascitic fluid, drain fluids, and pus aspirates, followed by biopsies (n = 82), lymph nodes (n = 43), urine (n = 19), and CSF (n = 3). GeneXpert MTB/RIF assay was positive in 10.3% (n = 30) samples, whereas negative in 89.7% (n = 260) samples. The overall sensitivity of GeneXpert MTB/RIF assay was 61.36% (95% CI 46.62%–74.28%), specificity 89.29% (95% CI 72.8%–96.29%), positive predictive value (PPV) 90% (95% CI 74.38%–96.54%), and negative predictive value (NPV) 59.52% (95% CI 44.49%–72.96%). Conclusion The GeneXpert MTB/RIF assay is a valuable tool for extrapulmonary tuberculosis. In addition to other tests like smear, culture GeneXpert MTB/RIF assay helps in the confirmation of diagnosis. Rapid diagnosis of tuberculosis with overall good sensitivity and specificity makes it a beneficial test.

Study of rapid detection of Mycobacterium Tuberculosis through GeneXpert MTB/RIF assay from acid fast bacilli smear-negative specimens in a Tertiary Care Hospital, Biratnagar Nepal

Introduction: Tuberculosis (TB) is an important public health concern around the world. It is well known that acid-fast bacilli (AFB) smear-negative TB cases are a major source of spreading TB to others when left untreated.
 Objectives: Our study aim to detect Mycobacterium tuberculosis (MTB) in AFB smear-negative samples through GeneXpert MTB/RIF assay and also to evaluate the drug resistance patterns towards Mycobacterium tuberculosis in hospitals.Methodology: This descriptive cross-sectional study was conducted among smear-negative presumptive TB patients at a tertiary care center with effect from September 2022 to September 2023 after approval from the Institutional Review Committee of the college. A convenience sampling method was used.
 Results: Out of 653 smear-negative samples, 71 (10.9%) were positive for TB and 17 (2.6%) were rifampicin resistance cases detected by GeneXpert MTB/RIF assay. The cases of tuberculosis were more in age groups between 46->60 years and least in 17-30 years of age. Pulmonary samples yielded a higher number of MTB 66 (92.95%) as compared to extra-pulmonary samples 5 (7.04%). There is an almost equal proportion of mycobacterium infection in males 37(52.11%) and females 34(47.88%). All the rifampicin resistance cases detected in our study were from pulmonary samples.
 Conclusion: Our study shows that the sensitivity of GeneXpert MTB/RIF assay is higher than AFB smear microscopy. We are missing actual TB cases while using AFB smear microscopy only. Hence the GeneXpert MTB/RIF assay is important for the rapid detection of MTB in smear-negative as well as smear-positive drug resistance MTB cases.

Diagnosis of Chest Wall Tuberculosis Using Fine Needle Aspiration: A Single-Center Experience.

Minimally invasive diagnosis of chest wall tuberculosis remains a challenge. Fine needle aspiration (FNA) is a simple and safe method of sampling. However, previous studies have shown that conventional tuberculosis tests had poor diagnostic performance in the needle aspirates. With the popularization of molecular detection application, the value of FNA in the diagnosis of chest wall tuberculosis needs to be reevaluated. We retrospectively studied patients with suspected chest wall tuberculosis at admission who underwent FNA for diagnosis and reported the diagnostic efficacy of acid-fast bacilli smear, mycobacterial culture, cytology and Xpert MTB/RIF (GeneXpert) when testing FNA specimens. A composite reference standard (CRS) was used as the diagnostic gold standard for this study. Among 89 included FNA specimens, acid-fast bacilli smear, mycobacterial culture, and GeneXpert were positive in 15 (16.85%), 23 (25.8%), and 61 (68.5%), respectively. Thirty-nine (43.8%) had cytologic features suggestive of tuberculosis. According to CRS, 75 (84.3%) cases were categorized as chest wall tuberculosis, 14 (15.7%) were not diagnosed with tuberculosis. Using CRS as the gold standard, acid-fast bacilli smear, mycobacterial culture, cytology and GeneXpert exhibited sensitivity of 20%, 30.7%, 52% and 81.3%, respectively. Specificity in these four tests was found to be 100%. Sensitivity of GeneXpert was significantly higher than that of smear, culture and cytology, X 2=66.3, p<0.001. GeneXpert achieved higher sensitivity as compared to cytology and conventional TB tests in the chest wall FNA specimens. Theimplementation of GeneXpert may increase the diagnostic efficacy of FNA in the diagnosis of chest wall TB.

Comparison of different diagnostic modalities for isolation of Mycobacterium Tuberculosis among suspected tuberculous lymphadenitis patients

Tuberculosis is a communicable disease with high morbidity and mortality rates in developing countries. The study's primary objective is to compare conventional methods such as acid-fast bacillus (AFB) culture and microscopy with rapid diagnostic methods. The secondary objective is to compare histopathological and microbiological findings in suspected patients with tubercular lymphadenitis. A total of 111 samples (August 2018 to September 2019) of lymph nodes were processed for AFB microscopy, AFB cultures, drug-susceptibility testing (DST), histopathology, and Xpert Mycobacterium Tuberculosis (MTB)/resistance to Rifampin (RIF) assays. Out of 111 lymph node samples, 6 (5.4%) were positive for AFB smear microscopy, 84 (75.6%) were positive for AFB culture, 80 (70.7%) were positive on Gene Xpert, and 102 (91.8%) were indicative of tuberculosis for histopathology studies. Mycobacteria growth indicator tube (MGIT) culture positivity was 84 (75.6%) higher than solid Lowenstein-Jensen (LJ) culture 74 (66.6%). Positive cultures underwent phenotypic DST. Two cases were Multidrug-resistant (MDR) on DST, while three cases were Rifampicin resistant on Gene Xpert. The sensitivity of Genexpert was (62%) against the conventional AFB culture method. The poor performance of conventional lymphadenitis diagnostic methods requires early and accurate diagnostic methodology. Xpert MTB/RIF test can help in the treatment of multidrug-resistant TB cases. Nonetheless, rapid and conventional methods should be used for complete isolation of Mycobacterium tuberculosis.

Molecular Approaches for Detection of Rifampin-Resistant Mycobacterium tuberculosis and Its Associated Risk Factors among General Population

GeneXpert MTB/RIF is a molecular technique for the diagnosis of tuberculosis. This method not only detects M. tuberculosis but also identifies the absence or presence of different drug resistant mutations in DNA fragments like rifampicin resistance. In this study, about 200 septum samples were collected from tuberculosis suspected people of Isfandyar Bukhari District Head Quarter Hospital Attock for screening and determination of Mycobacterium tuberculosis and multi-drug-resistant tuberculosis. The samples were screened for the presence of M. tuberculosis using Fluorescence Microscopy staining followed by GeneXpert MTB/RIF assay. The results were further confirmed by Line Probe Assay and Mycobacterium Growth Indicator Tube 960 techniques. In a total of 200 samples, 45(22.5%) were found positive, 155 (77.5%) were classified negative on culture while 38(19%) were positive and 162(81%) were negative on FM, 33(16.5%) were positive and 167(83.5%) were negative on ZN staining microscopy and 47(23.5%) were noted positive and 153 (76.5%) were negative on GeneXpert. The overall sensitivity of GeneXpert was 07% higher than that of smear microscopy and 4.2 % higher than culture.Different risk factors reported for TB are; malnutrition (23.40%), health care workers (14.89%), immunosuppression (12.76%), unimmunized with Bacille Calmette-Guérin (BCG) vaccine and contact with infected persons (10.63%), diabetes mellitus (8.51%), poverty and foreign-born children are (4.2%). It is concluded that the most common risk factor for TB was malnutrition (23.40%) and the foreign-born children (4.2%) were least affected. GeneXpert assay for identification of tuberculosis was found more sensitive than fluorescence microscopy and for isolation of MTB and rifampicin resistance, GeneXpert RIF assay can efficiently be usedwhich is simple, robust and efficient with minimum handling technique.

Evaluation of GeneXpert and liquid culture for detection of Mycobacterium tuberculosis in pediatric patients

PurposeEvaluation of GeneXpert in comparison to liquid culture using Mycobacteria Growth Indicator Tube (MGIT) as gold standard for detection of Mycobacterium tuberculosis (MTB) in children. MethodsA total of 8123 samples, both pulmonary (5830) and extra pulmonary (2293) received from pediatric patients were processed for Acid Fast Bacilli (AFB) smear, GeneXpert and MGIT culture simultaneously. ResultsOut of 8123 samples, 493 (6.1%) samples were found positive by GeneXpert and 508 (6.2%) samples by MGIT culture, 371 (4.6%) were found positive by both GeneXpert and MGIT culture. MGIT detected 137 (1.7%) extra positive than GeneXpert while GeneXpert detected 122 (1.5%) extra samples more positive than by MGIT. Sensitivity of GeneXpert was 73% and concordance between both methods was 96.8%. Rifampicin resistance was found in 49 (9.9%) samples among MTB positive by GeneXpert. Turnaround time for GeneXpert was approx. 2 ​h and for MGIT, it was 12–28 days. ConclusionGood sensitivity (73%) and concordance (96.8%) were observed for GeneXpert against MGIT culture in this study. GeneXpert can simultaneously detect MTB and rifampicin resistance in less than 2 ​h while MGIT takes 12–28 days for MTB detection only.

Diagnosis of Mycobacterium tuberculosis using GeneXpert MTB / RIF and TB-LAMP techniques from pulmonary and extra-pulmonary TB patients in Iraq

Tuberculosis is considered one globally public health problem, particularly in unindustrialized countries. The disease has an increasing threat to public health, causing high morbidity and mortality rates. So, rapid diagnosis is critical to diminish the death and interfere with transmission. In this study, GeneXpert MTB/RIF and Loop-Mediated Isothermal Amplification (TB-LAMP) assays were utilized for the rapid molecular diagnosis of Mycobacterium tuberculosis bacteria and compared sensitivity and specificity of Mycobacterium tuberculosis bacteria; these tests with acid-fast bacilli staining in pulmonary and extra-pulmonary clinical specimens from Iraqi patients in Baghdad capital. 141 pulmonary and extra-pulmonary samples were collected and tested for tuberculosis detection. Acid-fast bacilli, TB-LAMP and GeneXpert MTB/RIF methods were used to diagnose tuberculosis. Of 141 tuberculosis specimens, 58 were acid-fast bacilli smear-positive, while 90 samples were positive for Mycobacterium tuberculosis by GeneXpert MTB/RIF assay and 78 by TB-LAMP assay. The results reported a high sensitivity rate of GeneXpert MTB/RIF assay compared to the TB-LAMP and bacilli staining method. The sensitivity of GeneXpert was 63.83%, specificity 50%; positive and negative predictive values were 58.36% to 68.96% and 42.73% to 57.27%, respectively. TB-LAMP sensitivity was 55.32%, specificity 50%; positive and negative predictive values were 49.61% to 60.89% and 43.70% to 56.30%, respectively, while the sensitivity of bacilli staining was 41.13%, specificity 50%; positive and negative predictive values were 35.26% to 47.27% and 44.88% to 55.12%, respectively, these values are dependent on disease prevalence. We concluded that the GeneXpert MTB/RIF test is more sensitive and specific than the TB-LAMP and both techniques are more sensitive and specific than the conventional acid-fast staining method for both pulmonary and extra-pulmonary specimens. Despite culture remaining the gold standard for laboratory confirmation of TB, GeneXpert MTB/RIF and TB-LAMP should become standard practice for patients with suspected TB, and all clinicians and public health programs for TB control should have access to molecular testing for TB to shorten diagnosis time. Keywords. Mycobacterium tuberculosis; Pulmonary TB; Extrapulmonary TB; GeneXpert MTB/RIF; TB-LAMP; A.F.B

Comparative Studies of the Methods of Detecting Rifampicin Resistant Mycobacterium tuberculosis among Tuberculosis Patients Attending Aminu Kano Teaching Hospital, Kano

This study was conducted to compare the specificity and sensitivity of GeneXpert MTB/Rif and Lowenstein-Jensen (LJ) Proportion methods of detecting rifampicin-resistant Mycobacterium tuberculosis among Acid Fast Bacilli (AFB) positive patients attending the Directly Observed Treatment (DOT) Centre of Aminu Kano Teaching Hospital Kano. A total of 150 AFB positive samples were collected and processed according to the guideline given by National TB and Leprosy Control Program (2015) and WHO (2012), The result revealed that rifampicin-resistant Mycobacterium tuberculosis (RR-TB) from the samples was very high; 66.7% and 60.8% for GeneXpert MTB/Rif and Lowenstein-Jensen (LJ) Proportion methods respectively. Cohen’s Kappa (interrater reliability) statistical analysis indicated a substantial agreement between GeneXpert and LJ Proportion specificity and sensitivity (Kappa value = 0.73).&#x0D;

Efficacy of GeneXpert in Diagnosing Smear Negative Pulmonary Tuberculosis and Comparison to Culture

Objectives: Aim of present study is to observe the efficiency of GeneXpert MTB/RIF Assay in comparison to MTB culture on Lowenstein Jensen media in diagnosis of smear negative pulmonary tuberculosis cases.&#x0D; Methods: This descriptive study was carried out in The University of Lahore in collaboration with King Edward Medical University/Mayo Hospital Lahore 11th September, 2020 to 10th April 2021. Smear negative for acid fast bacilli patients enrolled for anti TB treatment were the target population. After taking informed consent, patients were asked to submit first morning sputum sample for culture on Lowenstein Jensen Medium and GeneXpert.&#x0D; Results: A total of 345 smear negative TB patients were diagnosed clinically and/or on the basis of radiological findings with mean age of 38.28±17.93,consisting of 47.5% male and 52.5% females recruited in this study. History of TB contact was present among 41.4% patients whereas history of smoking and diabetes remained to be 27.2% and 17.4% respectively. Culture showed significantly higher rate (35.1%) (p-value &lt;0.05) of detection of MTB as compared to GeneXpert (21.5%). A sensitivity of 56.01% was calculated for GeneXpert whereas for culture on LJ medium it was 60.63%.&#x0D; Conclusion: Sensitivity of GeneXpert MTB/RIF Assay is a bit low in diagnosing the SNPT patients as compared to the culture but still registers itself as a handsome tool in terms of promptness and definite detection of MTB complex. Further provision of rifampicin susceptibility is bonus in same time.

Spot specimen testing with GeneXpert MTB/RIF results compared to morning specimen in a programmatic setting in Cotonou, Benin

BackgroundThe diagnosis of tuberculosis (TB) using smear microscopy has been based on testing two specimens: one spot and one early morning sputa. Recently, the World Health Organization (WHO) has recommended to replace, whenever possible, microscopy with GeneXpert® MTB/RIF performed on a single specimen. However, as the bacterial load is higher in early morning specimens than in spot specimens, one could expect lower sensitivity of GeneXpert® MTB/RIF performed only on spot specimens. In this study, we compared results of GeneXpert® MTB/RIF on spot specimens versus early morning specimens, under programmatic conditions in Cotonou, Benin.MethodsFrom June to September 2018, all sputa received from presumptive TB patients at the Supranational Reference Laboratory for Tuberculosis of Cotonou were included in the study. From each patient, two specimens were collected (one spot and one early morning) and GeneXpert® MTB/RIF was performed on both specimens.ResultsIn total, 886 participants were included in the study, of whom 737 provided both sputa and 149 (16.8%) gave only the spot specimen. For the 737 participants who provided both sputa, GeneXpert® MTB/RIF was positive for both specimens in 152 participants; for three participants GeneXpert® MTB/RIF was positive on spot specimen but negative on morning specimen while for another three, the test was positive on morning specimen but negative on spot specimen. The overall percentage of agreement was excellent (99.2%) with a positive and negative percent agreement greater than 98%.ConclusionFor TB diagnosis under programmatic conditions in Cotonou, GeneXpert® MTB/RIF in spot specimens gave similar results with the test in morning specimens. Performing GeneXpert® MTB/RIF in both specimens did not significantly increase the number of cases detected. To avoid losing patients from the diagnostic cascade, it is preferable to test sputa produced at the time of the first visit at the health center.

Facteurs prédictifs et biomarqueurs de la pleurésie exsudative lymphocytaire tuberculeuse

Tuberculosis is the leading cause of exudative lymphocytic pleural effusion. To determine the predictive factors and assess the diagnostic performance of biomarkers for exudative lymphocytic tuberculous pleural effusion found in our practice. Case-control study from 01 January 2015 to 30 August 2019, including patients admitted to the day-hospital facility for pleural biopsy. Histopathology of pleural biopsy fragments was the gold standard for assessing the diagnostic performance of the biomarkers studied (pleural adenosine deaminase, geneXpert and pleural fluid culture). One hundred and nine patients were included. The average age was 35.7±18.1 years. In all, 72.5% of them were diagnosed with tuberculosis. After multivariate analysis, only patients aged under 35 years old were found to be at risk for exudative lymphocytic tuberculous pleural effusion (adjusted odds ratio: 9.18 [1.99; 42.28], P=0.004). Histopathology was suggestive of tuberculosis in 84.8% of cases (P<0.0001). The sensitivity of geneXpert was 42.1% and the specificity was 100%, with a mean concordance rate with histopathology (k=0.46). One case of rifampicin-resistant tuberculosis was detected by geneXpert (2.2%). The diagnostic performance of pleural adenosine deaminase varies according to the defined positivity threshold. For values greater than 70UI/L, its sensitivity was 25% and its specificity was 86.7%. The area under the ROC curve of the pleural adenosine deaminase was 0.70. In patients with exudative lymphocytic pleural effusion, young age is a risk factor for pleural tuberculosis. The geneXpert, although not very sensitive, is a moderately efficient and specific test for tuberculosis. Pleural adenosine deaminase is a discriminating and useful biomarker for the diagnosis of tuberculosis.

Diagnostic Accuracy of Gene Xpert on Bronchoscopy Washings in Patients with Suspected Pulmonary Tuberculosis

Objective: The objective of this study was to determine the diagnostic accuracy of GeneXpert assay of bronchial washing in detecting pulmonary tuberculosis in suspected TB patients with no sputum production taking culture of bronchial washing as gold standard. Methods: This is cross sectional study. Data was collected through structured questionnaire. Patients had bronchoscopy according to standard protocol. Their bronchial washings were sent for culture and GeneXpert assay for Mycobacterium Tuberculosis. Data analysis was done using SPSS 20 version. Results: From one hundred and seventy patients the age was observed as 16-60 years. AFB was detected by GeneXpert assay in 45.3% patients. AFB was detected by culture report in 47.6% patients. The sensitivity of GeneXpert was observed as 87.65%, specificity was 93.26%, and diagnostic accuracy was calculated as 90.59%. By using chi-square t-test, there was significant association found between GeneXpert and Culture report in both gender in all age groups with any duration of symptoms with p-value = 0.000. Conclusion: The GeneXpert assay was highly effective for detecting pulmonary tuberculosis in suspected TB patients who do not have sputum production. Key Words: GeneXpert Assay, Culture Report, Bronchial Washing, Pulmonary Tuberculosis How to Cite: Waseem A. K, Manzoor N, Javaid A, Musharaf M.S, Sohail N, Majeed N. Diagnostic accuracy of gene xpert on bronchoscopy washings in patients with suspected pulmonary tuberculosis. Esculapio.2020;16(04):33-36.

Detection of Mycobacterium tuberculosis in urine by GeneXpert MTB/RIF as a useful diagnostic tool in urinary tuberculosis

Background: Early and accurate diagnosis of urinary tuberculosis (UTB) is difficult as current diagnostic methods are lack of specificity (biochemical levels), lack of sensitivity (acid-fast bacilli stains), and time-consuming (TB culture). GeneXpert MTB/RIF has been endorsed by WHO and Indonesia Ministry of Health particularly for the sputum, and also gastric and lymph fluid samples. Given the limited data on the utility of GeneXpert MTB/RIF for urine samples, the recommendations do not apply to these samples. Case Description: A 38 y old woman was referred to the tertiary care hospital with suspected nephrolithiasis. She had a history of mild to moderate chronic flank pain and found to have left hydronephrosis on renal ultrasound. Ureteroscopy showed diffuse whitish necrosis of ureteral mucosa and ureteropelvic junction which was suspicious of tuberculous ureteritis. The acid-fast bacilli (AFB) smears gave negative result. Early morning sample was sent for GeneXpert MTB/RIF and the result was MTB detected with rifampin resistance not detected. The patient was managed with 6 m antituberculosis treatment according to the Ministry of Health regulation. Discussion: UTB was diagnosed using the urine AFB test, urine TB culture test and GeneXpert. Although the urine AFB test is simple, economical, and rapid, it has low sensitivity and specificity. TB culture has higher specificity compared AFB test but requires eight ws before the results are obtained. GeneXpert MTB/RIF, a real-time PCR, is a sensitive and specific test with 131 cfu/mL limit of detection that allows for early detection of TB. AFBs are intermittently shed in urine and the sensitivity of GeneXpert can be improved by using early morning urine for extended periods ranging from three to five days. Conclusion: GeneXpert MTB/RIF performed on urine samples is useful and can be recommended for rapid and reliable diagnosis of UTB in clinical practice esepecially in area with high TB burden. The diagnostic accuracy of urine GeneXpert MTB/RIF should be characterised further via prospective studies.

Role of automated GenexpertMTb/Rif system for rapid detection of Mycobacterium tuberculosis and Rifampicin resistance in extrapulmonary tuberculosis: A prospective study

Introduction: Extrapulmonary Tuberculosis is infection of mycobacterium tuberculosis involving organ other than lung. It account for 15-20% of all TB cases. Various combined approach used for diagnosis of Extrapulmonary TB. GeneXpert MTB/RIF System is cartridge based nucleic acid amplification test to detect tuberculosis and rifampicin resistance in two hours. Materials and Methods: This hospital based prospective study was carried out for period of 6 months with objective:-1) To evaluate the efficacy of GeneXpert MTB/RIF for the diagnosis of extrapulmonary tuberculosis (EPTB) by comparing it with composite reference standard which include smear microscopy, clinical findings at time of presentation and three months follow up and radiological investigations.2) To look for Rifampicin Resistance by GeneXpert. Results: Out of total of 168 enrolled patients 135 patients met the criteria of composite reference standard (CRS). Among total 135 CRS+ve EPTB Cases, 23 were paediatric (below 12 years of age) and 112 were Adults. Smear Microscopy was positive in 18 patients while GeneXpert gave positive results in 38 patients (8 paediatric and 30 adult patients). Rifampicin resistance was detected in 4 patients. Pleural effusion is the most commonly obtained sample followed by CSF, lymphnode, ascitic, urine, other fluid. Conclusions: Sensitivity of GeneXpert is more as compared to smear microscopy. GeneXpert showed better sensitivity in CSF, tissue, lymphnode, pleural and urine. So early microbiological diagnosis and Rifampicin drug sensitivity in Extrapulmonary sample lead to early treatment initiation of Tuberculosis and decrease morbidity and mortality due to tuberculosis. RNTCP has also recommended use of GeneXpert in suspected TB in Extrapulmonary sites. Keywords: GeneXpert, Extrapulmonary Tuberculosis, Smear Microscopy, Sensitivity.

A study to analyze the differences between GeneXpert MTB/RIF assay and LED fluorescent microscopy for the diagnosis of pulmonary tuberculosis in a tertiary care centre

cultures although being the gold standard for diagnosing tuberculosis has its limitations as it is time consuming. Thus newer methods using light-emitting diode fluorescent microscopy (LED-FM) and molecular methods like the GeneXpert MTB/RIF assay are being adopted as a mainstay for diagnosing tuberculosis around the globe. This observational descriptive study was carried out for a period of 21 months. Sputum samples from 110 adult subjects with a clinical suspicion of pulmonary tuberculosis (PTB) were stained for LED-FM microscopy and also inoculated into the GeneXpert assay. The positive smears were graded as per the Revised National Tuberculosis Control Programme (RNTCP) guidelines and positive GeneXpert assay results along with Rifampicin resistance were noted and analysed. Out of the 110 samples, (77.2%) were males and (22.7%) females. Of the 110 samples, 75 (68.1%) were positive for by the GeneXpert assay. In contrast with LED-FM, all 25 smear positive samples were also GeneXpert positive. Additionally, GeneXpert detected 10 smear negative cases. 10 (9%) positive GeneXpert isolates showed resistance to Rifampicin. The overall sensitivity of GeneXpert was greater but its specificity was comparable with LED-FM. The Xpert and LED-FM tests were comparable in specificity, but the GeneXpert assay out did the LED-FM as it was a more sensitive and rapid test for the diagnosis of tuberculosis and additionally detection of Rifampicin resistance. Our study fully agrees that the GeneXpert assay is a step ahead in the early diagnosis of tuberculosis even for smear negative cases of PTB. This assay is also a relatively simple and routine test that staff can perform with minimal training.

Comparison Study of GENEXPERT versus TB MGIT Culture in Extra Pulmonary Tuberculosis

Aims and objectives: To compare the diagnostic yield of Extra Pulmonary Tuberculosis, in terms of MTB isolation & detection of drug resistance via GENEXPERT & MGIT-DST culture methods. Materials and Methods: This was a prospective observational study carried out in Department of Pulmonary medicine, D.Y. Patil Hospital, Navi Mumbai. Study participants were patients above 18 years of age who had extra pulmonary tuberculosis and who were not already on Anti tuberculosis treatment in D.Y. Patil Hospital, Nerul, Navi Mumbai and willing to participate in the study and meeting all the inclusion criteria of the study. Study duration was from the date of approval by institutional ethics committee to October 2019.Sample size was 150 patients satisfying the inclusion criteria. Results: In our study, 28 % of all extra pulmonary samples were tested positive for TB MGIT culture out of which 35.2 % showed Resistance to 1st line ATT drugs on DST where as 39.33% was tested positive with Gene expert out of which 22.47% showed Rifampicin Resistance. Sensitivity of MGIT was 28.00 % and specificity was 39.50 %.Sensitivity of Genexpert was 39.33% and specificity was 26.5%. Conclusion: Our findings suggest that Gene Xpert may have a role in EPTB diagnosis in addition to PTB, particularly in low income/high-burden settings, where facilities for mycobacterial culture are limited. But Gene Xpert can detect only Rifampicin resistance where as DST by BACTEC MGIT AFB Culture detects other ATT drugs sensitivity too. Also the test results of MTB detected in GeneXpert in extra pulmonary samples was shown as low and very low based on the CT range (high, 28) as most of the extra pulmonary samples are pauci bacillary; hence the result is not totally reliable. Therefore, it should be confirmed by phenotypic DST by BACTEC MGIT Culture.

Role of Gene Xpert in the Detection of Genital Tuberculosis in Endometrial Tissue among Women with Infertility.

Objective:The objective of the study is to evaluate the clinical utility of Gene Xpert compared with other available diagnostic modalities in prompt diagnosis of female genital tuberculosis (TB) causing infertility.Material and Methods:This was a prospective, cross-sectional analytical study. Premenstrual endometrial biopsy specimens were collected from 176 infertile women of reproductive age group suspected of having genital TB. Samples were processed for acid-fast bacilli, culture, histopathology, polymerase chain reaction (PCR), and Gene Xpert. Patients detected positive on Gene Xpert and PCR were subjected to laparoscopy to look for affirmative findings of genital TB. The results were analyzed using composite gold standard consisting of patients positive with culture, histopathology, and laparoscopy.Results:A total of 18 patients were found positive using composite gold standard. Laparoscopy was positive in 15 patients, whereas culture and histopathology were positive in three and two patients, respectively. Gene Xpert was positive in two patients. None of them was detected with rifampicin resistance. The sensitivity of Gene Xpert was 11.11% whereas the specificity was 100%.Conclusion:Since genital TB is a paucibacillary disease, multiple diagnostic modalities are needed for diagnosis. Gene Xpert appears to be a useful modality in diagnosis of genital TB, owing to its high specificity, and can be recommended in conditions where microscopy, culture, and histopathology are negative; however, further randomized studies are required to support our hypothesis.

Role of GeneXpert in diagnosing tuberculous pleural effusion compared with thoracoscopic pleural biopsy

Background Pleural effusion caused by tuberculosis (TB) is a common form of extrapulmonary TB. It is usually cause by delayed hypersensitivity to antigens of tubercle bacilli in pleura. It is found that it occurs more in patients with HIV. Aim To evaluate the role of GeneXpert in diagnosing tuberculous pleural effusion compared with thoracoscopic pleural biopsy. Patients and methods This cross-sectional study was conducted on 71 patients with undiagnosed exudative pleural effusion, highly suspected to be tuberculous (as regarding our inclusive criteria). Tuberculin skin test, sputum Ziehl–Neelsen, thoracocentesis, GeneXpert examination, and pleural biopsy via thoracoscopy were done. Results Pleural fluid in most cases was rich in lymphocytes, and adenosine deaminase level (mean+SD) was 24.01±9.9. GeneXpert for pleural fluid was negative in 77.46%. The definitive diagnosis is to isolate tubercle bacilli from biological samples; if it is not available, diagnosis can be confirmed by histological examination of pleural tissue. Overall, 88.73% of the patients were diagnosed by histopathology. The sensitivity of GeneXpert was 22.2%, specificity was 75%, positive predictive value was 87.50%, negative predictive value was10.90%, and finally, its accuracy in evaluating TB pleurisy was very weak (28.6%). Conclusion With high suspicion of TB, GeneXpert may be performed first; if it gives positive data, it will be definite diagnosis, but if it gives negative data, patients should be subjected to further investigation, and the most confirmatory one is pleural biopsy. GeneXpert may save time for diagnosis. However, if negative, other confirmatory tests are mandatory. So GeneXpert has a good role in testing pleural TB.

A Study on Diagnostic Evaluation of Two Different Rapid DNA Polymerase Chain Reaction Techniques Namely Gene Xpert Mycobacterium Tuberculosis/Rifampin (MTB/RIF) and Mycoreal Polymerase Chain Reaction in the Diagnosis of Endometrial Tuberculosis Considering Culture as Gold Standard.

Context:The study involves the evaluation of two polymerase chain reaction (PCR) techniques one of which has been endorsed by the WHO for their diagnostic capabilities.Aims:The aim of this study is to evaluate the diagnostic accuracy of GeneXpert mycobacterium tuberculosis/Rifampin (MTB/RIF) and mycoreal PCR techniques in the diagnosis of endometrial tuberculosis (TB) considering culture as the gold standard.Settings and Design:A retrospective study conducted at Gunasheela surgical and maternity hospital. Patients who attended the outpatient department between January 2013 and August 2016, satisfying the eligibility criteria, were included in the study.Methodology:Women included in the study underwent endometrial pipelle sampling premenstrually after ruling out pregnancy in that cycle. Endometrial samples were tested for TB by Mycoreal PCR, Gene Xpert and BACTEC culture.Statistical Analysis Used:Statistical analysis was done using the R software version 3.6.1. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of test were calculated.Results:A total of 3229 samples were analyzed, of which 1754 were evaluated by Mycoreal TB PCR and 1475 were evaluated by Gene Xpert MTB/RIF assay. The sensitivity of mycoreal TB PCR technique was 34.78%, specificity was 99.08%, PPV was 33.33%, NPV was 99.13%, and accuracy was 98.23%. The sensitivity of GeneXpert MTB/RIF technique was 6.90%, specificity was 99.79%, PPV was 40.00%, NPV was 98.16%, and accuracy was 97.97%.Conclusions:MYCOREAL seemed to be more sensitive than Gene Xpert (MTB/RIF) considering culture as the gold standard in the diagnosis of endometrial TB.

Evaluation of GeneXpert MTB/RIF and BACTEC-MGIT 960 for the detection of tuberculosis among pneumoconiosis-associated tuberculosis patients

Objective: To evaluate the performence of GeneXpert MTB/RIF and BACTEC-MGIT 960 on detecting Mycobacterium tuberculosis and rifampicin resistance for pneumoconiosis-associated tuberculosis patients. Methods: The recruited 133 suspected active pneumoconiosis-associated tuberculosis hospitalized cases, morning sputum samples were collected to do modified L-J culture, conventional proportion method drug susceptibility test, GeneXpert MTB/RIF and BACTEC-MGIT 960. Analyze the sensitivity and specificity of the 133 sputum from patients, the positive rates of patients with tuberculosis in GeneXpert MTB/RIF test, BACTEC-MGIT 960 and modified L-J culture were 37.59%, 34.59% and 30.08% respectively. There was no significant difference among the three tests respectively (P>0.05) . According to the modified L-J culture, the sensitivity of GeneXpert MTB/RIF and BACTEC-MGIT 960 in detecting tuberculosis were 92.5% and 95.0% respectively, and specificity in rifampicin resistance were 86.0% and 91.4% respectively. There was no significant difference between GeneXpert MTB/RIF and BACTEC-MGIT 960 (P>0.05) . According to conventional proportion method drug susceptibility test, the sensitivity of GeneXpert MTB/RIF and BACTEC-MGIT 960 in detecting rifampicin resistance were 90.0% and 100%, and specificity were 92.6% and 96.4%. There was no significant difference between GeneXpert MTB/RIF and BACTEC-MGIT 960 (P>0.05) . Conclusion: The GeneXpert MTB/RIF has good performence of detecting tuberculosis and rifampicin resistance. It has good application value among pneumoconiosis-associated tuberculosis patients.