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Rapid microbiological screening for tuberculosis in HIV-positive patients on the first day of acute hospital admission by systematic testing of urine samples using Xpert MTB/RIF: a prospective cohort in South Africa.

Lawn SD, Kerkhoff AD, Burton R, Schutz C, van Wyk G, Vogt M, Pahlana P, Nicol MP, Meintjes G - BMC Med (2015)

Bottom Line: To evaluate a rapid screening strategy, we compared the diagnostic yield of Xpert testing sputum samples and urine samples obtained with assistance from a respiratory study nurse in the first 24 h of admission.The very high prevalence of active TB and its non-specific presentation strongly suggest the need for routine microbiological screening for TB in all HIV-positive medical admissions in high-burden settings.The incremental diagnostic yield from Xpert testing urine was very high and this strategy might be used to rapidly screen new admissions, especially if sputum is difficult to obtain.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK. stephen.lawn@lshtm.ac.uk.

ABSTRACT

Background: Autopsy studies of HIV/AIDS-related hospital deaths in sub-Saharan Africa reveal frequent failure of pre-mortem diagnosis of tuberculosis (TB), which is found in 34-64 % of adult cadavers. We determined the overall prevalence and predictors of TB among consecutive unselected HIV-positive adults requiring acute hospital admission and the comparative diagnostic yield obtained by screening urine and sputum samples obtained on day 1 of admission with Xpert MTB/RIF (Xpert).

Methods: To determine overall TB prevalence accurately, comprehensive clinical sampling (sputum, urine, blood plus other relevant samples) was done and TB was defined by detection of Mycobacterium tuberculosis in any sample using Xpert and/or mycobacterial liquid culture. To evaluate a rapid screening strategy, we compared the diagnostic yield of Xpert testing sputum samples and urine samples obtained with assistance from a respiratory study nurse in the first 24 h of admission.

Results: Unselected HIV-positive acute adult new medical admissions (n = 427) who were not receiving TB treatment were enrolled irrespective of clinical presentation or symptom profile. From 2,391 cultures and Xpert tests done (mean, 5.6 tests/patient) on 1,745 samples (mean, 4.1 samples/patient), TB was diagnosed in 139 patients (median CD4 cell count, 80 cells/μL). TB prevalence was very high (32.6 %; 95 % CI, 28.1-37.2 %; 139/427). However, patient symptoms and risk factors were poorly predictive for TB. Overall, ≥1 non-respiratory sample(s) tested positive in 115/139 (83 %) of all TB cases, including positive blood cultures in 41/139 (29.5 %) of TB cases. In the first 24 h of admission, sputum (spot and/or induced samples) and urine were obtainable from 37.0 % and 99.5 % of patients, respectively (P <0.001). From these, the proportions of total TB cases (n = 139) that were diagnosed by Xpert testing sputum, urine or both sputum and urine combined within the first 24 h were 39/139 (28.1 %), 89/139 (64.0 %) and 108/139 (77.7 %) cases, respectively (P <0.001).

Conclusions: The very high prevalence of active TB and its non-specific presentation strongly suggest the need for routine microbiological screening for TB in all HIV-positive medical admissions in high-burden settings. The incremental diagnostic yield from Xpert testing urine was very high and this strategy might be used to rapidly screen new admissions, especially if sputum is difficult to obtain.

No MeSH data available.


Related in: MedlinePlus

Tuberculosis (TB) diagnoses made by Xpert from urine and sputum samples collected in the first 24 h of hospital admission. Venn diagrams show diagnostic yields as proportions of (a) total TB diagnoses (n = 139), (b) TB diagnoses in patients with CD4 cell counts >100 cells/μL (n = 64) and (c) TB diagnoses in patients with CD4 cell counts ≤100 cells/μL (n = 74). Note: the CD4 cell count result was missing for one patient with TB
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Fig2: Tuberculosis (TB) diagnoses made by Xpert from urine and sputum samples collected in the first 24 h of hospital admission. Venn diagrams show diagnostic yields as proportions of (a) total TB diagnoses (n = 139), (b) TB diagnoses in patients with CD4 cell counts >100 cells/μL (n = 64) and (c) TB diagnoses in patients with CD4 cell counts ≤100 cells/μL (n = 74). Note: the CD4 cell count result was missing for one patient with TB

Mentions: With the aim of defining a day 1 rapid microbiological screening strategy for new admissions, we next compared the diagnostic yields of Xpert when testing whatever sputum and urine samples could be obtained during the first 24 h of admission (Table 5). The number (%) of cases diagnosed from urine was substantially increased by prior concentration of urine by centrifugation (unconcentrated urine yielded 59 of 139 (42.4 %) diagnoses, whereas concentrated urine yielded 82 of 139 (59.0 %) diagnoses; P = 0.006). Overall, 64.0 % (89 of 139) of all cases could be diagnosed from urine. In contrast, only 39 (28.1 %) cases could be diagnosed by Xpert testing sputum (Fig. 2a) (P <0.001), reflecting in large part the small proportion of patients able to produce sputum in the first 24 h of admission. Combined urine and sputum Xpert results gave the greatest diagnostic yield, detecting 108 of 139 (77.7 %) cases (Table 5).Table 5


Rapid microbiological screening for tuberculosis in HIV-positive patients on the first day of acute hospital admission by systematic testing of urine samples using Xpert MTB/RIF: a prospective cohort in South Africa.

Lawn SD, Kerkhoff AD, Burton R, Schutz C, van Wyk G, Vogt M, Pahlana P, Nicol MP, Meintjes G - BMC Med (2015)

Tuberculosis (TB) diagnoses made by Xpert from urine and sputum samples collected in the first 24 h of hospital admission. Venn diagrams show diagnostic yields as proportions of (a) total TB diagnoses (n = 139), (b) TB diagnoses in patients with CD4 cell counts >100 cells/μL (n = 64) and (c) TB diagnoses in patients with CD4 cell counts ≤100 cells/μL (n = 74). Note: the CD4 cell count result was missing for one patient with TB
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4537538&req=5

Fig2: Tuberculosis (TB) diagnoses made by Xpert from urine and sputum samples collected in the first 24 h of hospital admission. Venn diagrams show diagnostic yields as proportions of (a) total TB diagnoses (n = 139), (b) TB diagnoses in patients with CD4 cell counts >100 cells/μL (n = 64) and (c) TB diagnoses in patients with CD4 cell counts ≤100 cells/μL (n = 74). Note: the CD4 cell count result was missing for one patient with TB
Mentions: With the aim of defining a day 1 rapid microbiological screening strategy for new admissions, we next compared the diagnostic yields of Xpert when testing whatever sputum and urine samples could be obtained during the first 24 h of admission (Table 5). The number (%) of cases diagnosed from urine was substantially increased by prior concentration of urine by centrifugation (unconcentrated urine yielded 59 of 139 (42.4 %) diagnoses, whereas concentrated urine yielded 82 of 139 (59.0 %) diagnoses; P = 0.006). Overall, 64.0 % (89 of 139) of all cases could be diagnosed from urine. In contrast, only 39 (28.1 %) cases could be diagnosed by Xpert testing sputum (Fig. 2a) (P <0.001), reflecting in large part the small proportion of patients able to produce sputum in the first 24 h of admission. Combined urine and sputum Xpert results gave the greatest diagnostic yield, detecting 108 of 139 (77.7 %) cases (Table 5).Table 5

Bottom Line: To evaluate a rapid screening strategy, we compared the diagnostic yield of Xpert testing sputum samples and urine samples obtained with assistance from a respiratory study nurse in the first 24 h of admission.The very high prevalence of active TB and its non-specific presentation strongly suggest the need for routine microbiological screening for TB in all HIV-positive medical admissions in high-burden settings.The incremental diagnostic yield from Xpert testing urine was very high and this strategy might be used to rapidly screen new admissions, especially if sputum is difficult to obtain.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK. stephen.lawn@lshtm.ac.uk.

ABSTRACT

Background: Autopsy studies of HIV/AIDS-related hospital deaths in sub-Saharan Africa reveal frequent failure of pre-mortem diagnosis of tuberculosis (TB), which is found in 34-64 % of adult cadavers. We determined the overall prevalence and predictors of TB among consecutive unselected HIV-positive adults requiring acute hospital admission and the comparative diagnostic yield obtained by screening urine and sputum samples obtained on day 1 of admission with Xpert MTB/RIF (Xpert).

Methods: To determine overall TB prevalence accurately, comprehensive clinical sampling (sputum, urine, blood plus other relevant samples) was done and TB was defined by detection of Mycobacterium tuberculosis in any sample using Xpert and/or mycobacterial liquid culture. To evaluate a rapid screening strategy, we compared the diagnostic yield of Xpert testing sputum samples and urine samples obtained with assistance from a respiratory study nurse in the first 24 h of admission.

Results: Unselected HIV-positive acute adult new medical admissions (n = 427) who were not receiving TB treatment were enrolled irrespective of clinical presentation or symptom profile. From 2,391 cultures and Xpert tests done (mean, 5.6 tests/patient) on 1,745 samples (mean, 4.1 samples/patient), TB was diagnosed in 139 patients (median CD4 cell count, 80 cells/μL). TB prevalence was very high (32.6 %; 95 % CI, 28.1-37.2 %; 139/427). However, patient symptoms and risk factors were poorly predictive for TB. Overall, ≥1 non-respiratory sample(s) tested positive in 115/139 (83 %) of all TB cases, including positive blood cultures in 41/139 (29.5 %) of TB cases. In the first 24 h of admission, sputum (spot and/or induced samples) and urine were obtainable from 37.0 % and 99.5 % of patients, respectively (P <0.001). From these, the proportions of total TB cases (n = 139) that were diagnosed by Xpert testing sputum, urine or both sputum and urine combined within the first 24 h were 39/139 (28.1 %), 89/139 (64.0 %) and 108/139 (77.7 %) cases, respectively (P <0.001).

Conclusions: The very high prevalence of active TB and its non-specific presentation strongly suggest the need for routine microbiological screening for TB in all HIV-positive medical admissions in high-burden settings. The incremental diagnostic yield from Xpert testing urine was very high and this strategy might be used to rapidly screen new admissions, especially if sputum is difficult to obtain.

No MeSH data available.


Related in: MedlinePlus