The TST, a prick of a test

In 2002 the CDC ran an article about a study published in the Pediatric Infectious Disease Journal called Interpretation of the Tuberculin Skin Test Reaction by Pediatric Providers. The study said

The tuberculin (TB) skin test is widely used, but it is not easy to read...Many providers, regardless of professional training and experience, read a 15-mm TB skin test reaction as >10 mm, but a significant minority interpreted it as negative.

Khan and Starke, Texas Children’s Hospital, claim that for the skin test

most of even 15-mm reactions in children at low risk are false-positive results

which prompted them to call for better diagnosis of TB in children.

Ironically the PediatricSuperSite.com are running the "Blood assays outperform skin test in TB diagnosis" story.

Whilst Dr John Bradley continues to favour the skin test he does recommend IGRAs for some situations eg;

for a child with a positive skin test with no known exposures (these are presumed to be false-positive tuberculin skin tests, he said).

The problem, for Dr Bradley and others, is providing sufficient evidence that skin test reactions can be interpreted correctly and accurately. He maintains that for IGRA

There are insufficient data at present to recommend switching from tuberculin skin testing to an IGRA blood test for all kids

Employing the same argument there is now insufficient data to recommend using the TST.