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Influence of needle gauge in Mantoux skin testing
1Department of Infectious Diseases, St. Jude Children's Research Hospital.
Study Objective:
To determine the influence of needle gauge in Mantoux skin testing for tuberculosis.
Design:
Randomized selection of either a 27- or 30-gauge needle for Mantoux skin test placement; observer-blinded.
Setting:
Annual hospital employee screening.
Participants:
Six hundred twenty-five employees working in clinical and laboratory research environments.
Results:
Blinded observers found that the use of 27-gauge needles caused increased bleeding and bruising compared with 30-gauge needles (p < or = 0.007 for each). However, the 27-gauge needle produced larger blebs and less leakage of tuberculin solution (p < or = 0.0003).
Conclusion:
Smaller gauge needles could potentially cause false-negative screening results because of decreased antigen delivery. Use of needle gauges smaller than 27 gauge should be avoided until their reliability is validated.