scholarly journals Diagnostic Accuracy of Ziehl-Neelsen Smear Microscopy in Comparison with GeneXpert in Pulmonary Tuberculosis: A Multi-Center Study in Kandahar Province, Afghanistan

Author(s):  
Mujeeb Ahmad ◽  
Muhammad Haroon Stanikzai ◽  
Najeeb Rahimy ◽  
Abdul Wahed Wasiq ◽  
Hadia Sayam

Background: Tuberculosis (TB) is a major global health problem. The early and accurate diagnosis is crucial for disease management and to control disease transmission and the emergence of drug resistance TB. Objectives: This study was carried out to determine the diagnostic accuracy of Ziehl Neelsen (ZN) smear microscopy in comparison with GeneXpert MTB/RIF in pulmonary tuberculosis in Kandahar province, Afghanistan. Methods: This was a facility-based cross-sectional study. We scrutinized TB registers of three health facilities to include patients who had their sputum tested by both ZN smear microscopy and GeneXpert MTB/RIF. We extracted 734 patients’ data registered during January 2019 - June 2020 in a structured form. Kappa value was analyzed using SPSS version 19 software at 95% Confidence Interval (CI). We calculated sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) of ZN smear microscopy against GeneXpert MTB/RIF. Results: In comparison with GeneXpert as a reference test, ZN smear microscopy has 67.7% (95% CI:63.44%-70.74%) sensitivity and 100% (95% CI:98.74%-100.00%) specificity. The positive predictive value (PPV) and negative predictive value (NPV) were 100% and 99.89% (95% CI:99.88%-99.90%), respectively. The agreement between ZN smear microscopy and GeneXpert MTB/RIF results was moderate (70.4%) and the Kappa value was 0.45 (95% CI:0.38-0.59). Conclusion: This study has found high specificity but moderate sensitivity for the diagnosis of pulmonary TB using sputum ZN smear microscopy test. Hence, GeneXpert MTB/RIF test is more accurate and reliable for the diagnosis of pulmonary TB.

Author(s):  
Iqbal Rashid ◽  
Langalibalele H. Mabuza ◽  
Indiran Govender ◽  
Deidre Pretorius

Background: Optimum sputum results for acid-fast bacilli (AFB) microscopy are linked to a sputum quantity of at least 5.0 mL. This study was aimed at establishing the effect of sputum quantity in the pick-up rate of AFB microscopy by comparing sputum samples of 5.0 mL and 2.0 mL.Methods: An analytical cross-sectional study was carried out at the Dr George Mukhari Hospital (DGMH) in Pretoria, South Africa, from 05 January 2007 to 04 January 2008.Two sputum samples, 5.0 mL and 2.0 mL, were collected from each of the 330 adult PTB (pulmonary tuberculosis) suspects. Fluorescence microscopy was used in the sputum analysis. The yield through microscopy of the 2.0 mL specimen versus the 5.0 mL specimen was compared and analysed, using culture results as the gold standard.Results: From a sample of 330 specimens, 77 tested AFB positive on microscopy. In the 5.0 mL samples, the sensitivity was 76.6% (95% CI, 66.0% – 84.7%), specificity 99.6% (95% CI 97.8% – 99.9%), positive predictive value (PV+) 98.3% (95% CI 91.1% – 99.7%), negative predictive value (PV-) 93.3% (95% CI 89.7% – 95.7%), the likelihood ratio (LR) for a positive microscopy 192 and the LR for a negative test was 0.23. In the 2.0 mL specimens, the sensitivity was 75.3% (95% CI 64.6% – 83.6%), specificity 99.2% (95% CI 97.1% – 99.8%), positive predictive value (PV+) 96.7% (95% CI 88.6% – 99.1%), negative predictive value (PV-) 93.0% (95% CI 89.3% – 95.4%), the LR for a positive microscopy was 94 and 0.25 for a negative microscopy. There was a statistically significant association (p-value < 0.001) between the microscopy and culture tests in both the 5.0 mL and the 2.0 mL specimen categories. The strength of association between the microscopy and culture, as indicated by the kappa test was 0.83 and 0.81 in the 5.0 mL and 2.0 mL categories, respectively.Conclusion: Compared to the 2.0 mL specimen category, the yield for AFB microscopy in the 5.0 mL specimen category was consistently superior, as indicated by the higher sensitivity, specificity, predictive values and the likelihood ratios in the 5.0 mL specimen category. It is recommended that sputum specimen collection for AFB microscopy should aim for a minimum volume of 5.0 mL.


2021 ◽  
Vol 15 (12) ◽  
pp. 3175-3177
Author(s):  
Anum Iftikhar ◽  
Muhammad Arsalan ◽  
Sheeza Azaz ◽  
S H Waqar ◽  
Sajid Ali Shah ◽  
...  

Aim: To find out how accurate the Alvarado and Tzanaki scoring systems are in diagnosing acute appendicitis taking histopathology as gold standard. Methods: A cross-sectional prospective study was conducted from August 2019 to July 2020 at Department of General Surgery, Pakistan Institute of Medical Sciences Islamabad. Sixty patients were included, all of whom had appendectomies after a clinical diagnosis of acute appendicitis. Samples were submitted for histopathology, which was used as the gold standard for the definitive diagnosis of acute appendicitis. The specificity, sensitivity, positive predictive value (PPV), negative predictive value (NPV), diagnostic accuracy and negative appendectomy rate of Alvarado and Tzanaki scoring systems was calculated using SPSS version 23. Results: The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of Alvarado score at optimal cut-off threshold of ≥7.0, were calculated as 74%, 55%, 90%, 27% and 71.66% respectively. The cut-off threshold point of Tzanaki score was set at more than 8, which yielded a 94.11% sensitivity and an 88.88% specificity. The positive predictive value was 99.95% and the negative predictive value was 72.72%. The Alvarado and Tzanaki scoring systems had negative appendectomy rates of 9.5% and 2.04%, respectively. Conclusion: The Tzanaki scoring system has a better diagnostic accuracy for acute appendicitis as compared to the Alvarado score. Keywords: Acute appendicitis, Alvarado score, Tzanaki score


2020 ◽  
Vol 9 (3) ◽  
pp. 190-194
Author(s):  
Naureen Saeed ◽  
Fatima-tuz-zuhra ◽  
Nadeem Ikram ◽  
Farhana Shaukat ◽  
Fareeha Sardar

Background: Pakistan faces an immense burden of pulmonary tuberculosis (TB) due to large number of cases and limited resources. Despite the recent advancement in the diagnostic techniques for pulmonary TB, smear microscopy is still a useful technique for the diagnosis of this disease. This study was conducted in order to compare the diagnostic value of Auramine stain with the conventional Ziehl-Neelsen (ZN) stain on the sputum smear for the diagnosis of pulmonary TB, keeping GeneXpert MTB/RIF as the gold standard. Method: This cross-sectional study was conducted on 356 suspected patients of pulmonary TB referred to the Pathology laboratory from TB ward and OPD of District Head Quarter (DHQ) teaching hospital Rawalpindi, Pakistan. Sputum specimen were collected and two smears were prepared from each sputum sample on which Auramine phenol and Ziehl-Neelsen staining were carried out as per WHO recommendations. All these samples were further tested using Gene Xpert MTB/RIF technique. The sensitivity, specificity, Positive predictive value (PPV) and Negative predictive values (NPV) of ZN and Auramine stain were calculated and compared with GeneXpert MTB/RIF technique. Results: Out of the total 356 samples, 64(18%) were positive and 291(82%) were negative by GeneXpert which was taken as the gold standard. On comparison with GeneXpert, percentage of true positive was greater in case of Auramine than ZN stained samples (16.29% versus 12.92%), while the percentage of false positive was same for both staining techniques (0.28%). There were lesser false negative cases observed in samples stained by Auramine as compared to the ones stained by ZN (1.68% versus 5.05%). The sensitivity, specificity, positive predictive value and negative predictive values were 97.87%, 94.17%, 71.88 and 99.66%, respectively for the ZN staining and 98.31%, 97.98%, 90.63% and 99.66% respectively, for the Auramine phenol staining. Conclusion: Smear microscopy using Auramine phenol stain is a useful technique for the diagnosis of pulmonary TB. The Auramine phenol staining with fluorescent microscopy is found to be superior to ZN staining because of higher sensitivity and specificity. Keywords: Auramine phenol, Fluorescence microscopy, GeneXpert, Mycobacterium tuberculosis, Ziehl-Neelsen


2021 ◽  
Vol 15 (11) ◽  
pp. 3164-3165
Author(s):  
Mohammad Iltaf ◽  
Sana Akhtar ◽  
Dilaram Khan

Objective: To establish the diagnostic accuracy of BISAP in detecting the severe acute pancreatitis keeping computed tomography severity index as gold standard. Study Design: Cross-sectional study Place and Duration of Study: Department of Gastroenterology, Hayatabad Medical Complex, Peshawar from April 16th 2018 to 16th October 2018. Methodology: One hundred and twenty nine patients of age range of 18-60, of either gender having severe acute pancreatitis were included. While patients already diagnosed as severe acute pancreatitis and having known history of chronic pancreatitis were excluded. Patients were subjected to CT scan to confirm whether the severe acute pancreatitis is present or not. All CT scans were reported by single experiences radiologist. Results: There were 30.3% were males and 69.7% were females with mean age 42±11.03 years. BISAP had sensitivity 92.74%, specificity 80%, positive predictive value 99.13%, negative predictive value 20.76% and the overall diagnostic accuracy was 92.24%. Conclusion: BISAP had sensitivity 93.61%, specificity 100%, positive predictive value 100%, negative predictive value 40% and the overall diagnostic accuracy was 93.87% in severe acute pancreatitis keeping CT severity index as gold standard. Keywords: Accuracy, Severe acute pancreatitis, Computed tomography


2020 ◽  
Vol 27 (03) ◽  
pp. 499-505
Author(s):  
Mahwish Niaz ◽  
Mumtaz Ahmad ◽  
Kanwal Fatima ◽  
Faiza Kazi ◽  
Hassan Salim ◽  
...  

Pulmonary tuberculosis is one of the leading causes of infectious disease related mortality. Transbonchial biopsy and bronchoalveolar lavage smear obtained by bronchoscopy provides greater quantity of material for analysis, thus increases the chances of diagnosing the disease. Objectives: To diagnose sputum smear negative pulmonary tuberculosis patients by Transbronchial Biopsy and Bronchoalveolar smear keeping bronchoalvelar lavage culture as gold standard. To calculate and compare the diagnostic accuracy of transbronchial biopsy and bronchoalveolar lavage smear in sputum negative patients. Study Design: Cross-sectional validation study. Setting: Department of histopathology, Foundation University Medical College, Islamabad and Department of Pulmonology and Microbiology, Fauji Foundation Hospital, Rawalpindi. Period: From May 2016 to May 2017. Materials & Methods: It comprised 96 patients who underwent bronchoscopy. Transbronchial biopsy, bronchoalveolar lavage smear preparation and bronchoalveolar lavage culture was performed on specimens of all patients. Results: Out of 96 patients 22 (22.91%) patients were actually having tuberculosis whereas 74 (77%) had only clinical and radiological suspicion of tuberculosis. The mean age of patients was 43 years with a standard deviation of ±19.1 .The age range was 12-80 years. The sensitivity, specificity, positive predictive value, negative predictive value and true positives of transbronchial biopsy were 68.1%, 77%, 46.8%, 89% and15.62% while the values for bronchoalveolar lavage were 50%, 97.29%, 84.6%, 86.7% and 11.45% respectively. Thus, the diagnostic accuracy calculated for transbronchial biopsy and bronchoalveolar lavage was 75% and 13.54% respectively. Conclusions: Bronchoscopy should be done in all sputum negative tuberculosis patients having strong clinical and radiological suspicion to obtain transbronchial biopsy and bronchoalveolar lavage for timely diagnosis, treatment and prevention of disease transmission as well as to avoid empirical treatment and its side effects in patients having no tuberculosis. The diagnostic accuracy of transbronchial biopsy is almost 5 times more compared to bronchoalveolar lavage smear.


Author(s):  
Rainee Agrawal ◽  
Deepti Shrivastava

Background: Laparoscopy is considered as the gold standard for assessment of tubal factors of infertility, although because of its invasive nature, cost and the need for anaesthesia and hospitalization, HSG seems to be a basic routine procedure for tubal factors. Currently with the availability of the ultrasonography machines with very good resolution, SSG can be simultaneously practiced with ultrasonography during day 7-9 of the menstrual cycle to assess tubal patency. Hence, the present study was designed to compare the accuracy of HSG with SSG for evaluation of tubal factor infertility.Methods: This was a prospective cross-sectional study of 100 consecutive women with primary or secondary infertility without active pelvic infection, selected from OPD of Department of Obstetrics and Gynaecology, Acharya Vinoba Bhave Rural Hospital associated with Datta Meghe Institute of Medical Sciences University, Sawangi (Meghe), Wardha over a period of two years from September 2014 to August 2016.Results: In the present study for diagnosing tubal patency SSG had sensitivity of 88.64%, specificity of 75%, positive predictive value of 96.29% and negative predictive value of 47.36% and diagnostic accuracy of 87%, while HSG had sensitivity of 94.32%, specificity of 83.33%, positive predictive value of 97.64% and negative predictive value of 66.66% and diagnostic accuracy of 93%.Conclusions: Initial assessment of tubal patency by HSG is better than SSG as an indirect, outdoor, non-invasive procedure although with minimal radiation hazards. It allows documentation of tubal patency enables detection of several tubal lesions and permits assessments of the fine intratubal architectural details as well as little uterine pathology. It will help in reducing the number of laparoscopic procedures and their related complications and health care costs for confirmation of tubal patency.


2021 ◽  
Vol 7 (1) ◽  
pp. 88-93
Author(s):  
Silvani Permatasari ◽  
Vani Vrenika ◽  
Florence Felicia ◽  
Malasinta Malasinta ◽  
Ria Eriani ◽  
...  

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis. Indonesia is one of the developing countries with high TB patients in the world. The most common detection used for TB diagnosis is sputum smear examination. Smear negative pulmonary TB still have a risk of infection and can develop into active. The GeneXpert molecular examination is a rapid diagnosis of TB by the real-time PCR method. The purpose of this study was to assess the validity of GeneXpert in smear-negative pulmonary TB compared to Lowenstein Jensen's culture. The design of this diagnostic test study is a cross-sectional study. The study was conducted on 40 people with smear-negative pulmonary TB suspect patients in Dr. Doris Sylvanus Regional Hospital. Sputum examination was performed with GeneXpert and compared with Lowenstein Jensen culture. The results of GeneXpert validity for diagnosing smear-negative pulmonary TB suspect are sensitivity 81.8%, specificity 96.5%, positive predictive value 90%, negative predictive value 93.3%, and accuracy 92.5%. It was concluded that GeneXpert has sensitivity, specificity, positive predictive value, negative predictive value, and high accuracy as a diagnostic tool in smear-negative pulmonary TB suspects.


2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
M Moshage ◽  
S Smolka ◽  
S Achenbach ◽  
F Ammon ◽  
P Ferstl ◽  
...  

Abstract Background The accuracy of CT-derived FFR (FFRCT) has been repeatedly reported. However, the influence of lesion location on accuracy is unknown. Therefore, we evaluated the diagnostic accuracy of FFRCT to detect lesion-specific ischemia and determined the influence of lesion location (proximal vs. distal vessel segments) compared to invasively measured FFR in patients with suspected CAD. Methods A total of 136 vessels in which “Dual-Source”-CT coronary angiography had been performed due to suspected CAD and who were further referred for invasive coronary angiography with invasive FFR measurement within three months of the index CT examination were retrospectively identified and screened for inclusion in this analysis. Patients with either left main coronary artery stenoses, bifurcation or ostial stenoses were excluded. Invasive FFR was measured using a pressure wire (CERTUS®, St. Jude Medical, Minnesota, USA or Verrata®, Volcano, San Diego, USA). FFRCT was calculated using an on-site prototype (cFFR Version 3.0, Siemens Healthineers, Forchheim, Germany). All vessels were analyzed by an experienced observer blinded to the results of invasive FFR. Stenoses with invasively measured FFR ≤0.80 were classified as hemodynamically significant. We evaluated the diagnostic accuracy of FFRCT in proximal vs. non-proximal vessel segments. Proximal lesions included stenoses located in segment one, six, eleven and twelve. All other stenoses were categorized as distal lesions. Results Out of 136 coronary stenoses, 47 (35%) were located in proximal segments and 89 (65%) lesions were located in distal segments. Compared to invasive FFR, the sensitivity of FFRCT to correctly identify/exclude hemodynamically significant stenoses in proximal vessel segments was 93% (95% CI: 68–99.8%) and the specificity was 100% (95% CI: 89–100%), compared to a sensitivity of 72% (95% CI: 46.5–90%) and a specificity of 87% (95% CI: 77–94%) for FFRCT in distal lesions. The positive predictive value was 100% and the negative predictive value was 97% (95% CI: 82.8–99.5%) compared to a positive predictive value of 59% (95% CI: 42–93.9%) and a negative predictive value of 93% (95% CI: 85.4–96.3%) for proximal vs. distal vessel segment, respectively. This corresponds to an accuracy of 98% vs. 84%, respectively (p=0.02). ROC-Curve analysis showed a slightly higher – albeit non-significant – area under the curve for FFRCT to detect hemodynamic relevance in proximal lesions compared to distal lesions (AUC 0.95, p&lt;0.001 vs. AUC: 0.86, p&lt;0.001, respectively, p=0.2). Conclusion FFRCT obtained using an on-site prototype shows overall a high diagnostic accuracy for detecting lesions causing ischemia as compared to invasive FFR with a trend towards better diagnostic performance in proximal vessel segments. Funding Acknowledgement Type of funding source: None


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Mannix Imani Masimango ◽  
Michel P. Hermans ◽  
Espoir Bwenge Malembaka ◽  
Pierre Wallemacq ◽  
Ernest Kiswaya Sumaili ◽  
...  

Abstract Background Most studies of chronic kidney disease (CKD) in Sub-Saharan Africa (SSA) have been conducted in urban settings. They relied on GFR estimated from serum creatinine alone and on the inexpensive, convenient urinary dipstick to assess proteinuria. The dipstick for proteinuria has not been directly compared with the gold standard albumin-to-creatinine ratio (ACR) in a large-sized study in SSA. We hereby assessed the influence of rural versus urban location on the level, interpretation, and diagnostic performance of proteinuria dipstick versus ACR. Methods In a cross-sectional population-based study of CKD in both urban (n = 587) and rural (n = 730) settings in South-Kivu, Democratic Republic of Congo (DRC), we assessed the prevalence, performance (sensitivity, specificity, positive predictive value and negative predictive value) and determinants of a positive dipstick proteinuria as compared with albuminuria (ACR). Albuminuria was subdivided into: A1 (< 30 mg/g creatinine), A2 (30 to 299 mg/g creatinine) and A3 (≥ 300 mg/g creatinine). Results The overall prevalence of positive dipstick proteinuria (≥ 1+) was 9.6 % (95 % CI, 7.9–11.3) and was higher in rural than in urban residents (13.1 % vs. 4.8 %, p < 0.001), whereas the prevalence of albuminuria (A2 or A3) was similar in both sites (6 % rural vs. 7.6 % urban, p = 0.31). In both sites, dipstick proteinuria ≥ 1 + had a poor sensitivity (< 50 %) and positive predictive value (< 11 %) for the detection of A2 or A3. The negative predictive value was 95 %. Diabetes [aOR 6.12 (1.52–24.53)] was a significant predictor of A3 whereas alkaline [aOR 7.45 (3.28–16.93)] and diluted urine [aOR 2.19 (1.35–3.57)] were the main predictors of positive dipstick proteinuria. Conclusions ACR and dipstick proteinuria have similar positivity rates in the urban site whereas, in the rural site, dipstick was 2-fold more often positive than ACR. The poor sensitivity and positive predictive value of the dipstick as compared with ACR makes it unattractive as a screening tool in community studies of CKD in SSA.


2021 ◽  
Vol 10 (1) ◽  
pp. 20-25
Author(s):  
Sujan Shrestha ◽  
Mamen Prasad Gorhaly ◽  
Manil Ratna Bajracharya

Background Diabetic peripheral neuropathy (DPN) is a significant independent risk factor for diabetic foot, and an effective screening instrument is required to diagnose DPN early to prevent future ulceration and amputation. This study aims to determine the diagnostic accuracy of monofilament test to detect diabetic peripheral neuropathy. Methods This cross-sectional study was conducted in National Academy of Medical Sciences, Bir hospital, Mahabouddha, Kathmandu from February 2016 to January 2017. A total of 96 diabetic patients attending inpatient and outpatient Department were selected. Diabetic peripheral neuropathy was assessed by measurement of loss of protective sensation (LOPS) by monofilament test and compared with vibration perception threshold by standard biothesiometer. The sensitivity, specificity, positive predictive value and negative predictive value of monofilament test were calculated. Results The prevalence of diabetic peripheral neuropathy was 26%. The sensitivity, specificity, positive predictive value and negative predictive value of monofilament test were found to be 92.0%, 95.8%, 88.5% and 97.1% respectively. There was strong association between LOPS by monofilament and vibration perception threshold by biothesiometer. Conclusion This study showed a strong diagnostic accuracy of monofilament test to detect DPN when compared with biothesiometer. As monofilament test is a cheap, easily available, and portable, it can be used in the periphery where biothesiometer is not available.  


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