Spot Sputum Research Articles

Diagnostic performance of automated liquid culture and molecular line probe assay in smear-negative pulmonary tuberculosis.

The diagnosis of smear-negative pulmonary tuberculosis (PTB) is particularly challenging, and automated liquid culture and molecular line probe assays (LPA) may prove particularly useful. The objective of our study was to evaluate the diagnostic potential of automated liquid culture (ALC) technology and commercial LPA in sputum smear-negative PTB suspects. Spot sputum samples were collected from 145 chest-symptomatic smear-negative patients and subjected to ALC, direct drug susceptibility test (DST) testing and LPA, as per manufacturers' instructions. A diagnostic yield of 26.2% was observed among sputum smear-negative TB suspects with 47.4% of the culture isolates being either INH- and/or rifampicin-resistant. Complete agreement was observed between the results of ALC assay and LPA except for two isolates which demonstrated sensitivity to INH and rifampicin at direct DST but were rifampicin-resistant in LPA. Two novel mutations were also detected among the multidrug isolates by LPA. In view of the diagnostic challenges associated with the diagnosis of TB in sputum smear-negative patients, our study demonstrates the applicability of ALC and LPA in establishing diagnostic evidence of TB.

Implementing intensified tuberculosis case-finding among street-connected youth and young adults in Kenya.

Street-connected youth and young adults (SCY) suffer a myriad of health problems. In Kenya, SCY are at high risk for tuberculosis (TB) due to their congregate living situations. TB screening is not routinely implemented in SCY and there has been no published literature on the burden of TB in SCY in western Kenya. In 2011, the AMPATH TB Program, an experienced TB screening program, partnered with the Tumaini Center, a trusted street youth organization, to conduct intensified case finding (ICF) for pulmonary TB among SCY. Our program aimed to investigate the numbers of SCY who reported symptoms and those diagnosed with smear-positive pulmonary TB, and link SCY with TB to treatment. Of 116 SCY who were screened, 114 (98%) had a positive questionnaire; 104 (90%) provided a spot sputum sample, 39 (34%) provided a morning sputum sample, and 111 (97%) reported cough of >2 weeks. One street youth tested smear-positive for TB and was treated through to cure. Implementing TB ICF is feasible in low-resource settings through unique collaborations between health care programs and community-based organizations. In addition to identifying smear-positive TB, our program uncovered a high burden of respiratory symptoms among SCY in Eldoret, Kenya.

Adequacy of examining one sputum specimen in tuberculosis drug resistance surveys

Objective/backgroundCollection of one spot and one morning sputum specimen is recommended for tuberculosis (TB) drug resistance surveys. This was a retrospective analysis of Mycobacterium tuberculosis cultures isolated from two spot sputum specimens collected from smear positive TB patients in a TB drug resistance survey. It was conducted to understand the value of a second specimen. MethodsA TB drug resistance survey was conducted in the state of Tamil Nadu, India, to estimate the prevalence of drug resistance among new sputum smear-positive (NSP) and previously treated (PT) patients diagnosed in Revised National Tuberculosis Control Program microscopy centers. A total of 2425 patients (1524 NSP and 901 PT cases) were enrolled in the study. From these patients, two spot sputum specimens (C and D) were collected within a period of 2h. No preservative was added to sputum. The samples were transported at ambient conditions without cold storage to the central laboratory for culture of M. tuberculosis. Culture yield from each sample was computed and analyzed. ResultsThe proportion of cultures retrieved from C and D specimens among NSP cases (89.3% and 89.7%) and PT cases (90.8% and 90.3%) were similar. The culture grades of C and D samples were comparable (chi-square test, 3560.135; p<.001) and the agreement was moderate (kappa test, 0.454). ConclusionThe findings of the study reveal the adequacy of single spot sputum specimen from smear positive pulmonary TB patients for bacteriological examination in a quality-assured TB laboratory to determine precisely the level of drug resistance in a province of India.

Increased detection of smear-negative pulmonary tuberculosis by GeneXpert MTB/RIF® assay after bleach concentration

Objective/backgroundThe GeneXpert MTB/RIF assay (Xpert) was endorsed as the initial diagnostic tool in people suspected of human immunodeficiency virus-associated or drug-resistant tuberculosis (TB). However, information regarding the performance of Xpert for diagnosing smear-negative TB in high burden settings remains limited. We evaluated the diagnostic accuracy of Xpert and the impact of bleach concentration on the performance of Xpert using smear-negative sputum samples from human immunodeficiency virus-negative patients. MethodsOne spot and one morning smear-negative sputum samples per patient were examined using Xpert and culture at the Mycobacteriology Research Center of Jimma University, Ethiopia. The sputum culture on both Löwenstein–Jensen and/or Mycobacteria Growth Indicator Tube was the gold-standard. ResultsOf 185 smear-negative presumptive pulmonary TB cases, 19 (10.3%) had culture-proven TB. The sensitivity of Xpert on spot and morning sputum was similar (63.2%). Testing two specimens per patient insignificantly increased the sensitivity of Xpert. Bleach concentration and pelleting improved the sensitivity of Xpert over unprocessed sputum in paired samples (73.8% vs. 63.2%) without affecting the specificity (95%). Bleach concentration and pelleting allowed an additional seven cases of TB (missed on the first and second direct Xperts) to be detected, five of which were from culture-negative cases. ConclusionTesting of a single sputum sample by Xpert can reach reasonable sensitivity and results would be available on the same day, avoiding loss of patients and treatment delay. The sensitivity of Xpert was improved after bleach concentration and pelleting, although its added value needs further study on a larger scale.

Validation of smear-positive tuberculosis diagnoses in Bangladesh.

Questions have been raised as to the accuracy of smear-positive tuberculosis (TB) diagnoses at DOTS centres in Bangladesh. To assess the validity of diagnoses by smear microscopy at 62 DOTS centres in various health facilities. Using a cross-sectional study design, smear-positive TB cases were included from high, medium and low-performing DOTS centres from July to December 2010. The centres were categorised according to their case detection rate: centres with case detection rates of >70%, 50-70% and <50% were classed as high, medium and low-performing, respectively. Microscopy was performed on spot and early morning sputum samples for all cases. A convenience sample of 333 recently diagnosed smear-positive TB cases was included. The average number of patients enrolled per centre was 5.4; the highest number of cases was diagnosed from low-performing DOTS centres. Of the 333 cases, 302 (90.7%) were confirmed, while 31 (9.3%) were smear-negative. Differences in microscopy results could be due to the poor quality of the sputum sample, of smearing, staining or reading, or erroneous reporting by the DOTS centres. Preset programme targets and the nationwide drug stockout may have led to overreporting by the DOTS centres.

Detection of rifampicin resistance in tuberculosis by molecular methods: A report from Eastern Uttar Pradesh, India

Diagnosis of drug resistance tuberculosis (TB) by the gold standard method is labour intensive and time consuming. Hence, there is an urgent need for introduction of rapid diagnostic techniques. Line probe assay (LPA) and cartridge-based nucleic acid amplification test (CBNAAT) have been introduced in India under Revised National Tuberculosis Control Program. Spot and morning sputum samples of previously treated patients by anti-TB drugs were subjected to LPA or CBNAAT. Total 682/1253 (54.4%) were diagnosed as rifampicin-resistant. The patients could be diagnosed early by molecular methods and put on second line treatment.

The Yield of First Spot Double Slide Smears for the Diagnosis of Pulmonary Tuberculosis

Background: Direct sputum smear microscopy is the cornerstone for the diagnosis of pulmonary tuberculosis (PTB) in resource-poor countries. However, the requirement for repeated visits to submit specimens and receive results is associated with considerable diagnostic delay, work load, patients drop-out and high expenses for patients. Although the World Health Organization (WHO) has recently changed its policy from spot morning spot (SMS) to spot morning (SM), the SM method still involves two days visits for a patient. The aim of this study was to evaluate the yield of first spot double slides smears for the diagnosis of PTB in high TB setting. Methods: A total of 362 patients who visited the out-patient department (OPD) of Dilla referral hospital and who were suspected of PTB were involved in the study. In addition SMS sputum samples were collected; double slides smears were prepared, stained by the Ziehl-Neelsen (ZN) method and 100 fields were examined under oil immersion objective for acid fast bacilli (AFB). Results: Of 362, 54 (14.92%) were smear-positives. Out of the 54 smear positive patients, 53 (98.15%) were positives by the first spot specimen. Additionally, 1 of 54 (1.85%) were positives by the morning specimen. Using the 2-day protocol (SMS) among 362 patients, 54 (14.92%) were smear positives by double slides and 53 (14.64%) by single slide smears. Whereas using the 1-day protocol (first spot); among 362 patients, 53 (14.64%) were smear positives both in double slides and single slide smears. Conclusion: The double slides smears from the first spot sputum samples appeared to be as effective as SMS strategy for the diagnosis of PTB though additional studies are required under various settings.

Predictors for MTB Culture-Positivity among HIV-Infected Smear-Negative Presumptive Tuberculosis Patients in Uganda: Application of New Tuberculosis Diagnostic Technology.

BackgroundThe existing World Health Organization diagnostic algorithms for smear-negative TB perform poorly in HIV-infected individuals. New TB diagnostics such as urine TB lipoarabinomannan (LAM) could improve the accuracy and reduce delays in TB diagnosis in HIV-infected smear-negative presumptive TB. We sought to determine predictors for MTB culture-positivity among these patients.MethodsThis study was nested into a prospective evaluation of HIV-infected outpatients and inpatients clinically suspected to have TB who were screened by smear-microscopy on two spot sputum samples. Data on socio-demographics, clinical symptoms, antiretroviral therapy, CXR, CD4 count, mycobacterial sputum and blood cultures and TB-LAM were collected. Logistic regression and conditional inference tree analysis were used to determine the most predictive indicators for MTB culture-positivity.ResultsOf the 418 smear-negative participants [female, 64%; median age (IQR) 32 (28-39) years, median CD4 106 (IQR 22 - 298) cells/mm3], 96/418 (23%) were sputum and/ or blood culture-positive for Mycobacterium tuberculosis (MTB) complex. Abnormal CXR (aOR 3.68, 95% CI 1.76- 7.71, p=0.001) and positive urine TB-LAM (aOR 6.21, 95% CI 3.14-12.27, p< 0.001) were significantly associated with MTB culture-positivity. Previous TB treatment (aOR 0.41, 95% CI 0.17-0.99, p=0.049) reduced the likelihood of a positive MTB culture. A conditional inference tree analysis showed that positive urine TB-LAM and abnormal CXR were the most predictive indicators of MTB culture-positivity. A combination of urine TB-LAM test and CXR had sensitivity and specificity of 50% and 86.1% respectively overall, and 70.8% and 84.1% respectively among those with CD4<100 cells/mm3.ConclusionsA positive urine TB-LAM test and an abnormal CXR significantly predict MTB culture-positivity among smear-negative HIV-infected presumptive TB patients while previous TB treatment reduces the likelihood of a positive MTB culture. Validation studies to assess the performance of diagnostic algorithms that include urine TB-LAM in the diagnosis of smear-negative TB in HIV-infected individuals are warranted.

Screening for TB by sputum culture in high-risk groups in Copenhagen, Denmark: a novel and promising approach

IntroductionEvidence on screening high-risk groups for TB by mobile X-ray in low-incidence countries is building, but knowledge on other possible screening methods is limited. In this retrospective study we report...

The diagnostic accuracy of urine lipoarabinomannan test for tuberculosis screening in a South African correctional facility.

BackgroundWe evaluated the diagnostic accuracy of the urine lipoarabinomannan (LAM) antigen detection assay (Clearview TB-ELISA) to screen for tuberculosis in a South African correctional facility.MethodsBetween September 2009 and October 2010, male offenders were screened for tuberculosis (symptoms, chest radiograph, two spot sputum specimens for microscopy and culture), and urine tested for LAM. Sensitivity, specificity and predictive values of LAM were calculated using definite and probable tuberculosis combined as our gold standard.Findings33/871 (3.8%) participants (26% HIV-positive) had tuberculosis. Amongst HIV-positive vs. HIV-negative offenders the sensitivity and specificity of LAM was 7.1% vs. 0% and 98.5% vs. 99.8% respectively.ConclusionUrine LAM ELISA has inadequate sensitivity for TB screening in this population.

Pulmonary Tuberculosis and Its Risk Factors among Inmates of a Ghanaian Prison

Aims: To determine the prevalence of Pulmonary Tuberculosis (PTB) and its risk factors among prison inmates at the Ho central prison . Study Design : Cross - sectional study. Place and Duration of Study: Ho C entral Prison in the Ho Municipality of the Volta Region, between May and June 2014. Methodology: We included 389 prisoners who were screened using the World Health Organization PTB tool. Consenting suspected PTB case - patients were interviewed using a str uctured questionnaire. Variables collected were socio - demographic and prison - related factors. Spot and early morning sputum samples were collected from suspected case - patients for sputum smear microscopy. Prevalence of PTB and risk f actors were determined. Significance level

The Yield of First Spot Double Slide Smears for the Diagnosis of Pulmonary Tuberculosis

Background: Direct sputum smear microscopy is the cornerstone for the diagnosis of pulmonary tuberculosis (PTB) in resource-poor countries. However, the requirement for repeated visits to submit specimens and receive results is associated with considerable diagnostic delay, work load, patients drop-out and high expenses for patients. Although the World Health Organization (WHO) has recently changed its policy from spot morning spot (SMS) to spot morning (SM), the SM method still involves two days visits for a patient. Objective: This study evaluated the yield of first spot double slides smears for the diagnosis of PTB in high TB setting. Methods: A total of 362 patients who visited the out-patient department (OPD) of Dilla referral hospital and who were suspected of PTB were involved in the study. In addition SMS sputum samples were collected; double slides smears were prepared, stained by the Ziehl–Neelsen (ZN) method and 100 fields were examined under oil immersion objective for acid fast bacilli (AFB). Results: Of 362, 54(14.92%) were smear-positives. Out of the 54 smear positive subjects, 53 (98.15%) were positives by the first spot specimen. Additionally, 1 of 54 (1.85%) were positives by the morning specimen. Using the 2-day protocol (SMS) among 362 patients, 54(14.92%) were smear positives by double slides and 53(14.64%) by single slide smears. Whereas using the 1-day protocol (first spot); among 362 patients, 53(14.64%) were smear positives both in double slides and single slide smears. Conclusion: The double slides smears from the first spot sputum samples appeared to be as effective as SMS strategy for the diagnosis of PTB though additional studies are required under various settings.

Evaluation of the Xpert MTB/RIF assay for diagnosis of tuberculosis and rifampin resistance in county-level laboratories in Hunan province, China

Background The Xpert MTB/RIF showed high sensitivity and specificity in previous studies carried out in different epidemiological and geographical settings and patient populations in high-burden tuberculosis (TB) countries. However, there were little data obtained by validation or demonstration study of the assay in China. In this study, the performance of Xpert MTB/RIF was investigated in two county-level laboratories in Hunan Province, China. Methods Consecutive patients with suspected pulmonary tuberculosis (PTB) and suspicion for multidrug-resistant tuberculosis (MDR-TB) were enrolled. For each patient suspected to have PTB, three sputum specimens (one spot sputum, one night sputum, and one morning sputum) were collected and each sputum was tested with smear microscopy, Löwenstein-Jensen (LJ) culture, and Xpert MTB/RIF test. For comparison across subgroups and testing methods, 95% confidence intervals were calculated. All analyses were done with SPSS 16.0, and P &lt;0.05 was regarded as significant. Results For case detection, the sensitivity of Xpert MTB/RIF was 100% for smear- and culture-positive TB and 88.6% for smear-negative and culture-positive TB; the overall sensitivity was 94.5% for all culture-positive patients. The specificity was 99.8%. The sensitivity of Xpert MTB/RIF assay was 22.0% in clinical TB patients and the specificity reached 100.0% in the group of patients who are infected with nontuberculous mycobacteria. For the detection of rifampin resistance, the sensitivity of MTB/RIF RIF-resistance detection was 92.9%, and the specificity was 98.7%. Of the 26 Xpert MTB/RIFpositive and RIF-resistant patients confirmed by LJ proportion tests, 20 (76.9%) patients were infected by MDR-TB. Conclusions The Xpert MTB/RIF assay is a highly sensitive and specific method for diagnosis of TB and RIF resistance, which will enable it to have the potential to be used in county-level laboratories and lead to the reduction of the infectious pool and improvements in TB control in China. Further evaluations in county-level laboratories for implementing the assay are still required.

A multicenter study of Cross-Priming Amplification for tuberculosis diagnosis at peripheral level in China

Cross-Priming Amplification (CPA) has been shown to rapidly and effectively detect Mycobacterium tuberculosis (MTB) in sputum samples under isothermal conditions. However, no performance data exist from peripheral-level tuberculosis (TB) clinics in tuberculosis-endemic countries. We conducted a clinical trial at four county-level TB clinics in China to evaluate the effectiveness of the CPA assay. TB suspects were continuously enrolled by a clinician at each clinic. Following informed consent, each patient provided two sputum specimens (spot and morning sputum). Sputum samples were tested by smear microscopy, solid culture and CPA. The National TB reference laboratory (NTRL) collected all culture positive strains and performed 16S-23S rDNA internal transcribed spacer (ITS) sequence analysis for strain identification. Solid culture was used as the gold standard to evaluate the effectiveness of CPA in detecting MTB. A total of 2200 TB-suspected patients were enrolled at the four county-level TB clinics. Compared to solid culture, the sensitivity and specificity of the CPA test for MTB detection within this group was 84.1% (95%CI, 79.5-88.6) and 97.8% (95%CI, 97.1-98.5), respectively, and the sensitivity in smear-negative cases was 59.8% (95%CI, 49.8-69.8). The test failure rate of CPA was 0.8% (32/3918), significantly lower than the 1.7% (106/6138) culture contamination rate.

Diagnostic accuracy of the PURE-LAMP test for pulmonary tuberculosis at the county-level laboratory in China.

BackgroundEarly and effective detection of Mycobacterium tuberculosis (MTB), particularly in smear-negative tuberculosis (TB), is a priority for global TB control. Loop-mediated isothermal amplification with a procedure for ultra rapid DNA extraction (PURE-LAMP) can detect TB in sputum samples rapidly and with high sensitivity and specificity. However, the PURE-LAMP test has not been effectively evaluated, especially in resource-limited laboratories. In this study, we evaluated the performance of the PURE-LAMP test for TB detection in TB suspects from two county-level TB dispensaries in China.Methodology/Principal FindingsFrom April 2011 to February 2012, patients with suspected TB were continuously enrolled from two county-level TB laboratories in China. Three sputum samples (spot, night, and morning sputum) were collected from each recruited patient. Detection of MTB by PURE-LAMP was compared to a reference standard L-J culture. The results showed that the sensitivity of the PURE-LAMP test based on spot sputum for MTB detection was 70.67%, while the sensitivity of the PURE-LAMP test based on spot sputum for MTB detection in smear positive and culture positive patients and smear negative and culture positive patients was 92.12% and 53.81%, respectively. The specificity of PURE-LAMP based on spot sputum for MTB detection was 98.32%. The sensitivity and specificity of the PURE-LAMP test based on three sputa combination for MTB detection was 88.80% and 96.86%, respectively. The results also showed that the PURE-LAMP test had a significantly lower contamination rate than did solid culture.Conclusions/SignificanceThe study suggested that, in peripheral-level TB laboratories in China, the PURE-LAMP test showed high sensitivity and specificity for TB detection in TB suspects, making it a more effective, rapid, and safe method worthy of broader use in the future.

The Sensitivity and Specificity of Using a Computer Aided Diagnosis Program for Automatically Scoring Chest X-Rays of Presumptive TB Patients Compared with Xpert MTB/RIF in Lusaka Zambia

ObjectiveTo determine the sensitivity and specificity of a Computer Aided Diagnosis (CAD) program for scoring chest x-rays (CXRs) of presumptive tuberculosis (TB) patients compared to Xpert MTB/RIF (Xpert).MethodConsecutive presumptive TB patients with a cough of any duration were offered digital CXR, and opt out HIV testing. CXRs were electronically scored as normal (CAD score ≤60) or abnormal (CAD score>60) using a CAD program. All patients regardless of CAD score were requested to submit a spot sputum sample for testing with Xpert and a spot and morning sample for testing with LED Fluorescence Microscopy-(FM).ResultsOf 350 patients with evaluable data, 291 (83.1%) had an abnormal CXR score by CAD. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of CXR compared to Xpert were 100% (95%CI 96.2–100), 23.2% (95%CI 18.2–28.9), 33.0% (95%CI 27.6–38.7) and 100% (95% 93.9–100), respectively. The area under the receiver operator curve (AUC) for CAD was 0.71 (95%CI 0.66–0.77). CXR abnormality correlated with smear grade (r = 0.30, p<0.0001) and with Xpert CT(r = 0.37, p<0.0001).ConclusionsTo our knowledge this is the first time that a CAD program for TB has been successfully tested in a real world setting. The study shows that the CAD program had high sensitivity but low specificity and PPV. The use of CAD with digital CXR has the potential to increase the use and availability of chest radiography in screening for TB where trained human resources are scarce.

Pulmonary tuberculosis among diabetic patients in Dharan Municipality, Eastern Nepal

Background: Tuberculosis (TB) remains a major cause of morbidity and mortality throughout the world. People with diabetes mellitus (DM) have a three times higher risk of developing active tuberculosis than people without diabetes. However, there is no such study has been carried out previously on the burden of pulmonary tuberculosis (PTB) among diabetic patients in Dharan. Therefore, this study was conducted to determine the prevalence of tuberculosis among diabetic patient. Methods & Materials: A cross-sectional study conducted in tuberculosis laboratory, BPKIHS. Spot sputum specimens were collected from 100 known diabetic patients. The sputum samples were initially stained using Ziehl-Neelsen stain for detection of acid fast bacilli (AFB) followed by culture in Lowenstein Jensen Media according to national tuberculosis centre(NTC) guidelines. Data was entered in Microsoft Excel and analyzed using the SPSS version 11.0 statistical software and p-value <0.05 was considered as significant. Results: Out of 100 diabetic patients, 8 were positive for pulmonary tuberculosis. Among them6weremale. Seven patients had history of diabetes longer than 5 years and 5 of them were under insulin therapy. Among the positive cases, 7 patients were above 30 years of age. Of the total positive cases 6 patientswere identified by microscopic examination, however all AFB positive specimens yielded the growth of Mycobacterium tuberculosis in LJ medium. Conclusion: The study reveals that prevalence of pulmonary tuberculosis among diabetic patient is high though the sample size was small.

Same day sputum smear microscopy approach with modified ZN staining for the diagnosis of pulmonary tuberculosis in a microscopy centre at Rajahmundry

Background: Sputum smear microscopy is the main-stay in the diagnosis of pulmonary tuberculosis in many developing countries. To overcome the drop outs, same day diagnosis is ideal. Materials and Methods: In the current study, two spot sputum samples (SS2 approach) are collected within a gap of one hour (same day sputum smear microscopy) in addition to the standard spot morning (SM) approach. The smears were stained with standard Ziehl Neelsen (ZN) and modified ZN staining techniques. Results: Out of 1537 patients, sputum smear positivity (SSP) was 9.43% (146 patients) in SM approach with standard ZN staining. Smear positivity was increased to 9.8% (151 patients) with modified ZN staining. For SS2 approach, SSP was 9.37% (144 patients) and 9.8% (151 patients) with standard and modified ZN staining procedures, respectively. Conclusions: Diagnosis of lung tuberculosis is possible with two spot sputum samples with modified ZN staining.

What is the most reliable solid culture medium for tuberculosis treatment trials?

We conducted a prospective study to determine which solid medium is the most reliable overall and after two months of therapy to detect Mycobacterium tuberculosis complex (MTB). MTB isolation and contamination rates on LJ and Middlebrook 7H10 and 7H11 agar with and without selective antibiotics were examined in a single laboratory and compared against a constructed reference standard and MGIT 960 results. Of 50 smear positive adults with pulmonary TB enrolled, 45 successfully completed standard treatment. Two spot sputum specimens were collected before treatment and at week 8 and one spot specimen each at weeks 2, 4, 6, and 12. The MTB recovery rate among all solid media for pre-treatment specimens was similar. After 8 weeks, selective (S) 7H11 had the highest positivity rate. Latent class analysis was used to construct the primary reference standard. The 98.7% sensitivity of 7H11S (95% Wilson confidence interval 96.4%-99.6%) was highest among the 5 solid media (P=0.003 by bootstrap); the 82.6% specificity of 7H10S (95% CI 75.7%-87.8%) was highest (P=0.098). Our results support 7H11S as the medium of choice. Further studies in different areas where recovery and contamination are likely to vary, are recommended.

High Tuberculosis Prevalence in a South African Prison: The Need for Routine Tuberculosis Screening

BackgroundTuberculosis is a major health concern in prisons, particularly where HIV prevalence is high. Our objective was to determine the undiagnosed pulmonary tuberculosis (“undiagnosed tuberculosis”) prevalence in a representative sample of prisoners in a South African prison. In addition we investigated risk factors for undiagnosed tuberculosis, to explore if screening strategies could be targeted to high risk groups, and, the performance of screening tools for tuberculosis.Methods and FindingsIn this cross-sectional survey, male prisoners were screened for tuberculosis using symptoms, chest radiograph (CXR) and two spot sputum specimens for microscopy and culture. Anonymised HIV antibody testing was performed on urine specimens. The sensitivity, specificity and predictive values of symptoms and investigations were calculated, using Mycobacterium tuberculosis isolated on sputum culture as the gold standard.From September 2009 to October 2010, 1046 male prisoners were offered enrolment to the study. A total of 981 (93.8%) consented (median age was 32 years; interquartile range [IQR] 27–37 years) and were screened for tuberculosis. Among 968 not taking tuberculosis treatment and with sputum culture results, 34 (3.5%; 95% confidence interval [CI] 2.4–4.9%) were culture positive for Mycobacterium tuberculosis. HIV prevalence was 25.3% (242/957; 95% CI 22.6–28.2%). Positive HIV status (adjusted odds ratio [aOR] 2.0; 95% CI 1.0–4.2) and being an ex-smoker (aOR 2.6; 95% CI 1.2–5.9) were independently associated with undiagnosed tuberculosis. Compared to the gold standard of positive sputum culture, cough of any duration had a sensitivity of 35.3% and specificity of 79.6%. CXR was the most sensitive single screening modality (sensitivity 70.6%, specificity 92.2%). Adding CXR to cough of any duration gave a tool with sensitivity of 79.4% and specificity of 73.8%.ConclusionsUndiagnosed tuberculosis and HIV prevalence was high in this prison, justifying routine screening for tuberculosis at entry into the prison, and intensified case finding among existing prisoners.