INFLUENCE OF NEEDLE GAUGE IN MANTOUX SKIN TESTING

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-bl inded. Setting: Annual hospital employee screening. Participants: Six hundred twenty-five employees working in clinical and laboratory resea rch environments. Results: Blinded observers found that the use of 27- gauge needles caused increased bleeding and bruising compared with 30- gauge needles (p less than or equal to 0.007 for each). However, the 2 7-gauge needle produced larger blebs and less leakage of tuberculin so lution (p less than or equal to 0.0003). Conclusion: Smaller gauge nee dles could potentially cause false-negative screening results because of decreased antigen delivery. Use of needle gauges smaller than 27 ga uge should be avoided until their reliability is validated.