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Am Fam Physician. 2023;108(2):119

Incorrect recommendation. In the article “Tuberculosis: Common Questions and Answers” (September 2022, p. 308), the recommended cutoff age for interferon-gamma release assay (IGRA) testing was listed incorrectly. In the first paragraph of the “What Are the Advantages and Disadvantages of TST vs. IGRA?” section, the second-to-last sentence (p. 309) should have read, “Disadvantages of IGRA testing include cost, and it is not recommended for use in children younger than two years.” An additional reference has been added to the online version of this article for this sentence and for a footnote in Table 2: Nolt D, Starke JR. Tuberculosis infection in children and adolescents: testing and treatment. Pediatrics. 2021;148(6):e2021054663. In Table 2 (p. 310), one of the cons listed for QuantiFERON-TB Gold+ should have read, “Not recommended for children younger than two years*” with the following accompanying footnote: “Guidelines from the Centers for Disease Control and Prevention and the American Thoracic Society state five years and older, but the American Academy of Pediatrics guidelines state two years and older.32” The online version of the article has been corrected.

Test characteristicTuberculin skin testQuantiFERON-TB Gold+T-SPOT.TB
FormatPurified protein derivative injected intradermally; patient must return in 48 to 72 hours for resultsEnzyme-linked immunosorbent assay using whole blood; processed within 16 hoursEnzyme-linked immunosorbent spot test using peripheral blood mononuclear cells; processed in eight to 24 hours (up to 32 hours if T-Cell Xtend is used)
MeasurementSize of skin indurationInterferon-gamma levelInterferon-gamma level
Sensitivity (%)68.994.195.6
Specificity (%)5997.397.1
Positive likelihood ratio1.6834.8532.97
Negative likelihood ratio0.5950.0290.030
Results affected by BCG vaccination?YesNoNo
ProsLower costHigh specificity
Objective results
High specificity
Objective results
Only reacts to Mycobacterium tuberculosis, not other mycobacterial strains
ConsRequires at least two separate visits
Affected by BCG vaccination status
False-negative risk if recent live vaccination
Subjective results
Misreading of skin test results
Not recommended for children younger than two years*
Potential for improper handling and processing
Not approved for children younger than two years*
Different reactivity criteria in the United States, Canada, Europe

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