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The proportions of people living with HIV in low and middle-income countries who test tuberculin skin test positive using either a 5 mm or a 10 mm cut-off: a systematic review.

Kerkhoff AD, Gupta A, Samandari T, Lawn SD - BMC Infect. Dis. (2013)

Bottom Line: Using a cut-off of ≥10 mm, the median proportion of PLWH testing TST-positive was 19.6% (IQR, 13.7-36.8%; range 0-52.1%).The median difference in the proportion of PLWH testing TST-positive using the two cut-offs was 6.0% (IQR, 3.4-10.1%; range, 0-37.6%).This proportion was similar across the range of CD4+ cell strata, supporting the current standardization of this cut-off at all levels of immunodeficiency.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: A positive tuberculin skin test (TST) is often defined by skin induration of ≥10 mm in people who are HIV-seronegative. However, to increase sensitivity for detection of Mycobacterium tuberculosis infection in the context of impaired immune function, a revised cut-off of ≥5 mm is used for people living with HIV infection. The incremental proportion of patients who are included by this revised definition and the association between this proportion and CD4+ cell count are unknown.

Methods: The literature was systematically reviewed to determine the proportion of people living with HIV (PLWH) without evidence of active tuberculosis in low and middle-income countries who tested TST-positive using cut-offs of ≥5 mm and ≥10 mm of induration. The difference in the proportion testing TST-positive using the two cut-off sizes was calculated for all eligible studies and was stratified by geographical region and CD4+ cell count.

Results: A total of 32 studies identified meeting criteria were identified, providing data on 10,971 PLWH from sub-Saharan Africa, Asia and the Americas. The median proportion of PLWH testing TST-positive using a cut-off of ≥5 mm was 26.8% (IQR, 19.8-46.1%; range, 2.5-81.0%). Using a cut-off of ≥10 mm, the median proportion of PLWH testing TST-positive was 19.6% (IQR, 13.7-36.8%; range 0-52.1%). The median difference in the proportion of PLWH testing TST-positive using the two cut-offs was 6.0% (IQR, 3.4-10.1%; range, 0-37.6%). Among those with CD4+ cell counts of <200, 200-499 and ≥500 cells/μL, the proportion of positive tests defined by the ≥5 mm cut-off that were between 5.0 and 9.9 mm in diameter was similar (12.5%, 12.9% and 10.5%, respectively).

Conclusions: There is a small incremental yield in the proportion of PLWH who test TST-positive when using an induration cut-off size of ≥5 mm compared to ≥10 mm. This proportion was similar across the range of CD4+ cell strata, supporting the current standardization of this cut-off at all levels of immunodeficiency.

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Forest plot showing the difference in proportions (%, 95% CI) of people living with HIV testing TST-positive using a ≥5 mm versus a ≥10 mm cut-off size with data grouped according to CD4+ cell count strata (<200, 200–499 and ≥500 cells/μL).
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Figure 3: Forest plot showing the difference in proportions (%, 95% CI) of people living with HIV testing TST-positive using a ≥5 mm versus a ≥10 mm cut-off size with data grouped according to CD4+ cell count strata (<200, 200–499 and ≥500 cells/μL).

Mentions: Nine studies with a total of 5,107 PLWH reported the proportion of those testing TST-positive using both a ≥5 mm and a ≥10 mm cut-off size stratified by CD4+ cell counts at <200, 200–499, ≥500 (Table 2). These CD4+ cell count stratified data are shown in a forest plot (Figure 3). The median difference in the proportion of PLWH testing TST-positive using the two induration cut-off sizes was 2.0% (range, 0–10.7%; IQR, 0–7.8%), 3.5% (range, 1.5-7.8%; IQR, 2.7-4.4%) and 6.0% (range, 2.6-20.9%; IQR, 4.9-9.6%) among those with CD4+ cell counts <200, 200–499, ≥500 cells/μL, respectively. The corresponding proportions of positive tests defined by the ≥5 mm cut-off that were between 5.0 and 9.9 mm in diameter were 12.5% (IQR, 0–16.0), 12.9% (IQR, 7.6-15.2), 10.5% (IQR, 9.1-28.5), respectively [9-40].


The proportions of people living with HIV in low and middle-income countries who test tuberculin skin test positive using either a 5 mm or a 10 mm cut-off: a systematic review.

Kerkhoff AD, Gupta A, Samandari T, Lawn SD - BMC Infect. Dis. (2013)

Forest plot showing the difference in proportions (%, 95% CI) of people living with HIV testing TST-positive using a ≥5 mm versus a ≥10 mm cut-off size with data grouped according to CD4+ cell count strata (<200, 200–499 and ≥500 cells/μL).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3716635&req=5

Figure 3: Forest plot showing the difference in proportions (%, 95% CI) of people living with HIV testing TST-positive using a ≥5 mm versus a ≥10 mm cut-off size with data grouped according to CD4+ cell count strata (<200, 200–499 and ≥500 cells/μL).
Mentions: Nine studies with a total of 5,107 PLWH reported the proportion of those testing TST-positive using both a ≥5 mm and a ≥10 mm cut-off size stratified by CD4+ cell counts at <200, 200–499, ≥500 (Table 2). These CD4+ cell count stratified data are shown in a forest plot (Figure 3). The median difference in the proportion of PLWH testing TST-positive using the two induration cut-off sizes was 2.0% (range, 0–10.7%; IQR, 0–7.8%), 3.5% (range, 1.5-7.8%; IQR, 2.7-4.4%) and 6.0% (range, 2.6-20.9%; IQR, 4.9-9.6%) among those with CD4+ cell counts <200, 200–499, ≥500 cells/μL, respectively. The corresponding proportions of positive tests defined by the ≥5 mm cut-off that were between 5.0 and 9.9 mm in diameter were 12.5% (IQR, 0–16.0), 12.9% (IQR, 7.6-15.2), 10.5% (IQR, 9.1-28.5), respectively [9-40].

Bottom Line: Using a cut-off of ≥10 mm, the median proportion of PLWH testing TST-positive was 19.6% (IQR, 13.7-36.8%; range 0-52.1%).The median difference in the proportion of PLWH testing TST-positive using the two cut-offs was 6.0% (IQR, 3.4-10.1%; range, 0-37.6%).This proportion was similar across the range of CD4+ cell strata, supporting the current standardization of this cut-off at all levels of immunodeficiency.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: A positive tuberculin skin test (TST) is often defined by skin induration of ≥10 mm in people who are HIV-seronegative. However, to increase sensitivity for detection of Mycobacterium tuberculosis infection in the context of impaired immune function, a revised cut-off of ≥5 mm is used for people living with HIV infection. The incremental proportion of patients who are included by this revised definition and the association between this proportion and CD4+ cell count are unknown.

Methods: The literature was systematically reviewed to determine the proportion of people living with HIV (PLWH) without evidence of active tuberculosis in low and middle-income countries who tested TST-positive using cut-offs of ≥5 mm and ≥10 mm of induration. The difference in the proportion testing TST-positive using the two cut-off sizes was calculated for all eligible studies and was stratified by geographical region and CD4+ cell count.

Results: A total of 32 studies identified meeting criteria were identified, providing data on 10,971 PLWH from sub-Saharan Africa, Asia and the Americas. The median proportion of PLWH testing TST-positive using a cut-off of ≥5 mm was 26.8% (IQR, 19.8-46.1%; range, 2.5-81.0%). Using a cut-off of ≥10 mm, the median proportion of PLWH testing TST-positive was 19.6% (IQR, 13.7-36.8%; range 0-52.1%). The median difference in the proportion of PLWH testing TST-positive using the two cut-offs was 6.0% (IQR, 3.4-10.1%; range, 0-37.6%). Among those with CD4+ cell counts of <200, 200-499 and ≥500 cells/μL, the proportion of positive tests defined by the ≥5 mm cut-off that were between 5.0 and 9.9 mm in diameter was similar (12.5%, 12.9% and 10.5%, respectively).

Conclusions: There is a small incremental yield in the proportion of PLWH who test TST-positive when using an induration cut-off size of ≥5 mm compared to ≥10 mm. This proportion was similar across the range of CD4+ cell strata, supporting the current standardization of this cut-off at all levels of immunodeficiency.

Show MeSH
Related in: MedlinePlus