The point where resistance to pen displacement occurs determines the outer limit of the induration. A ballpoint pen line may be drawn on the transverse axis of the forearm, starting 1–2 cm away from the visible skin test reaction and moving slowly towards its centre, exerting moderate pressure against the skin. Measure the induration. Alternatively, use the ballpoint pen method for reading. Do not measure the diameter of the redness, swelling or bruising.Using a plastic scale or ruler, place the zero ruler line inside the edge of marked fine line or dot and measure the ruler line inside the right dot or the alternate edge of the fine line. If the measurement falls between two divisions on the millimetre scale, record the lower division. The diameter of induration is measured across the forearm, from the thumb side of the arm to the little finger side.If the margins of the induration are irregular, mark and measure the widest diameter. Using the fingertip as a guide, lightly mark the widest edges of the induration across the forearm with a fine line or dot. Sweep fingertips over the surface of forearm in all four directions to locate margins or edges of induration. The reader should gauge the presence of induration (palpable, raised, hardened area or swelling), starting with inspection and then palpation with light, gentle motion. Reading should be performed in good light, with the forearm slightly flexed at the elbow.The test should be read 48–72 hours after the injection (not before 48 hours or after 72 hours). ![]() If the wheal is less than 6 mm in diameter, the test should be repeated at a site at least 5 cm away from the original site. When the correct injection technique is used, a pale wheal measuring 6–10 mm in diameter will result. ![]() If a drop of blood appears, gently blot the injection site with alcohol-based disinfectant without squeezing out tuberculin.If there is no leakage, continue to inject slowly until the complete 0.1 mL solution has been administered, and then remove the needle quickly. Release the stretched skin and slowly inject tuberculin and check for leakage. After gentle cleaning of the site with an alcohol swab, stretch the selected area of the skin using the thumb and forefinger, insert the needle slowly with the bevel pointing upwards at an angleof 5–15 degrees, and advance the needle through the epidermis approximately 3 mm so the entire bevel is covered and visible just under the skin.Tuberculin should be injected within 20 minutes of loading to the syringe.Draw 0.1 mL (5 TU) of tuberculin, or as per the manufacturer’s instructions, and expel air and excess drops.Clean the top of the vial with a sterile swab.Use a 1 mL graduated syringe or tuberculin syringe that can dispense 0.1 mL solution accurately using a short (8–13 mm) 27-gauge needle.Check the expiry date on the vial and ensure the vial contains tuberculin PPD-S (5 TU/0.1 mL) or PPD RT 23 (2 TU/0.1 mL). ![]() It should be discarded if the fluid changes colour or after 30 days. The vial can be used up to 1 month after opening. The vials should be stored at 2–8 ☌ without exposure to direct sunlight.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |