Look at the vial label to make sure the vial contains the tuberculin that you want to use, including the tuberculin unit strength.
The label should indicate the expiration date. If it's been open more than 30 days or the expiration date has passed, the vial should be thrown away and a new vial used.
When you open a new vial, write the date and your initials on the label to indicate when the vial was opened and who opened it.
To avoid reducing the potency of the tuberculin, store it inside a refrigerator so that it remains between 35 and 46 degrees Fahrenheit or between 2 and 8 degrees Centigrade.
Also store and transport the tuberculin in the dark as much as possible and avoid exposure to light.
In certain settings, such as when you're in the field, you may need to use another type of cooling container to control the temperature and protect from light.
After collecting supplies, the next step is patient education. You should sit so that you are both comfortable and facing each other.
Discuss why the skin test is given, what is involved in the procedure, and when the patient should return for the test to be read. Explain that 48 to 72 hours after the test is administered, the patient must return to have the induration measured and evaluated. Make an appointment for the patient to return.
If a patient can't return within the 48- to 72-hour time period, do not administer the test. Instead, schedule another time that allows the patient to come for both the test and the return appointment.
It's also important to encourage the patient to ask questions and talk about any anxieties he or she may have about the test.
That way you can answer any questions and ease any fears the patient may have. Consult local practice to find out how best to document informed consent in your setting.
After providing patient education, you should wash your hands, using an appropriate hand-washing technique, before administering the test or any other procedure involving patient contact. In certain field settings it may be necessary to use other hand-hygiene techniques.
On a firm, well-lit surface, expose the patient's arm and slightly flex it at the elbow. The injection should be placed on the palm-side-up surface of the forearm, about 2 to 4 inches below the elbow. Your local institutional policy may specify the right or the left forearm for the skin test.
The area selected should be free of any barriers to placing and reading the skin test such as muscle margins, heavy hair, veins, sores, or scars.
If the patient has any of these at the site, then you should use the other arm or the standard alternative site selected by your institution.
After choosing the injection site, clean the area with an alcohol swab by circling from the center of the site outward. Allow the site to dry completely before the injection. Because some of the tuberculin solution can adhere to the inside of the plastic syringe, the skin test should be given as soon as possible after the syringe is filled.
Always follow your institution's standard precautions for infection control.
Wipe the top of the vial with a new alcohol swab before drawing up the tuberculin solution.
Pick up the syringe and be sure to fasten the needle tightly on the syringe by holding the cap and twisting it onto the tip of the syringe. Next, remove the needle cap.
The needle bevel should be perpendicular to the flange of the syringe. If necessary, turn and tighten the needle to line up the bevel correctly with the flange.
Place the vial on a flat surface, hold the vial between the thumb and fingers, and insert the needle through the neoprene stopper.
Invert the vial while keeping a firm hold on the syringe and plunger. The tip of the needle should be below the fluid level in the vial.
Pull back on the plunger and draw out slightly more than the one tenth of a milliliter needed for the test.
Remove the needle from the vial. Hold the syringe in an upright position, then draw back slightly on the plunger. Tap the syringe lightly to break up air bubbles, then push forward.
Expel all air and excess fluid from the syringe and needle, leaving exactly one tenth of a milliliter of tuberculin solution in the syringe.
The second step in administering the Mantoux tuberculin skin test is injection. You'll inject the tuberculin, discard the needle and syringe, check that the skin test was administered properly, and repeat the test if needed.
Stretch taut the selected area of skin between the thumb and forefinger.
This provides a surface that is easier for the needle to penetrate. With the needle bevel facing up and the syringe flange parallel to the forearm, hold the syringe between your thumb and forefinger.
The Mantoux tuberculin skin test is an intradermal injection.
With the needle bevel against the patient's skin, insert it slowly at a 5- to 15-degree angle.
The 5- to 15-degree angle is very important because this layer of skin is very thin.
For an intradermal injection, the needle bevel is advanced through the epidermis, the superficial layer of skin, approximately 3 mm so that the entire bevel is covered and lies just under the skin.
The injection will produce inadequate results if the needle angle is too deep or too shallow.
When the needle is inserted at the correct angle you can see the bevel of the needle just below the skin surface. Next, release the stretched skin and hold the syringe in place on the forearm.
Grip the flange of the syringe between your first and middle fingers. Use your thumb to press on the plunger.
Now, slowly inject the tuberculin solution. You should feel fairly firm resistance as the tuberculin enters the skin. A tense, pale wheal that's 6 to 10 mm in diameter appears over the needle bevel. Remove the needle without pressing or massaging the area.
Next, discard the used syringe immediately in the designated puncture-resistant container.
If you're using a safety needle, engage the safety-needle mechanism before discarding.
To prevent needlestick injuries, used needles should not be recapped, purposely bent or broken, removed from disposable syringes, or otherwise manipulated by hand.
It's not unusual for a drop of blood to appear at the injection site, even when the needle is inserted properly.
Should this happen, lightly blot the blood away with a 2x2 gauze pad or cotton ball. Do not cover the site with an adhesive bandage because the adhesive could cause irritation and interfere with the test. Properly dispose of the contaminated gauze pad. To determine if the skin test was administered properly, use the millimeter ruler to immediately measure the wheal at its maximum size.
The wheal should be at least 6 mm in diameter.
If the wheal is less than 6 mm in diameter, then the test should be administered again.
The needle bevel may have been inserted too deeply or an inadequate dose administered.
If leakage occurs at the insertion site, the needle bevel may not have been inserted far enough for the bevel to be covered by the skin.
If the tuberculin test must be repeated, use another site at least 2 inches, or 50 mm, from the original site. Or use the standard alternate placement site. You will need to indicate this alternate site when you fill out the record keeping forms.
The final step in administering the Mantoux tuberculin skin test includes washing your hands, recording information, reminding the patient about the return visit, providing patient education, and returning the vial to the refrigerator.
In this step, immediately and thoroughly wash your hands.
This step also includes recording information on the patient's chart and other record-keeping forms. Write the date and the time the test was administered, the name and manufacturer of the injected solution, the lot number, the tuberculin dose administered, the expiration date, the forearm or alternative site in which the injection was given, the site location if you repeat the test, the name of the person who administered the test, and the reason for giving the skin test.
Since it's important for the patient to return within 48 to 72 hours to have the test result read, always remind the patient to return. Giving the patient a card with information on care of the site and the date for the return appointment may help serve as a reminder.
Explain that mild itching, swelling, or irritation may occur and that these are normal reactions that do not require any treatment. These types of reactions usually go away within a week. Explain how to care for the injection site after the test.
Tell the patient to avoid scratching the site, keep the site clean and dry, and avoid putting creams, lotions, or adhesive bandages on it. Also mention that getting the site wet with water is not harmful, but the site should not be wiped or scrubbed.
Finally, return the tuberculin vial to the refrigerator, or other cooling container if you are in the field.
Released October 2008
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