Tuberculin PPD RT 23 AJV Dosage/Direction for Use

Skin-testing should be performed using the Mantoux method. When used for a medical diagnostic purpose, it is recommended to apply 0.1 ml of 2 T.U. of Tuberculin PPD RT 23 AJV. The dose is 0.1 ml of the PPD RT 23 solution. The injections should be given intradermally in the middle third of the forearm, as reactions are weaker near the wrist and the elbow joint.
A 1 ml graduated syringe with a short-bevelled 25-26 gauge needle (0.5 x 10 mm) is recommended for administration. Slightly more than 0.1 ml of the tuberculin solution should be drawn up.
An excess volume, as well as any air bubbles, is removed, leaving exactly 0.1 ml Tuberculin PPD solution.
The skin is lightly stretched, and the needle point (bevel upwards) is inserted in the superficial layer of the skin, after which the entire dose of 0.1 ml is slowly injected.
It is essential that the injection be given in the uppermost layer of the skin, as the subsequent reaction is difficult to interpret if the Tuberculin PPD solution is injected too deeply.
A suitable injection will result in the immediate formation of a small round wheal or papule of 8-10 mm in diameter, which will remain visible for about 10 minutes.
If no wheal is formed, the solution may have been given too deeply, and the skin test should be repeated at another site, 4 or more centimetres away from the first injection.
Evaluation and interpretation of the Mantoux Test: 48-72 hours after an injection, an induration, possibly surrounded by an area of redness, can be observed in positive reactors. Measure only the induration, however, approximately 3 days after the application of Tuberculin PPD RT 23 AJV.
The skin reaction can be felt as a flat, uneven, slightly raised induration which should be measured using a clear, flexible plastic ruler.
A positive reaction to Tuberculin PPD RT 23 AJV is defined as an induration having a diameter of more than 6 mm. (See table.)

Click on icon to see table/diagram/image

Countries where BCG vaccination is practised may wish to choose a higher cut-off point to indicate a positive reaction. Under certain circumstances, immunosuppressed individuals may be considered to react positively to tuberculin, even though the induration is less than 6 mm in diameter.