Tuberculin (Intradermal)

Also known as purified protein derivative (PPD), tuberculin is a mixture of proteins that are used to determine whether a person suffers from tuberculosis.

Overview

The PPD diagnostic test itself in the medical realm is known as tuberculin skin test and is highly recommended for those persons at a high risk of contracting tuberculosis. PPD is injected into the skin through a patient's forearm. After 2 to 3 days if the injected skin area develops a severe swelling, the test is considered positive. Mantoux test is another term that's frequently used to refer to PPD tuberculin test provided by intradermal injection. All the same, the medicine is issued in a hospital or clinic by or under the supervision of a doctor.

Robert Koch was the mastermind behind the discovery and formation of tuberculin, way back in 1890. According to the World Health Organization's List of Essential Medicines, tuberculin is considered one of the most effective and safest drugs vital in the health system. The drug is also easily available and affordable in many parts of the world.

Conditions treated

  • Tuberculosis

Type of medicine

  • Tuberculin skin test or tuberculosis blood test

Side effects

Some of the common side-effects associated with tuberculin include itchiness, redness, and pain around the area of injection. Others include bleeding, blistering, and scabbing at the injection site, frequent coughing, dizziness, fainting, fever, fast heartbeat, hives, and difficult and noisy breathing. Also, swelling of the eyelids or around the eyes, tongue, lips, or face are other common side-effects, as well as fatigue.

Sometimes, though only occasionally, allergic reactions may also occur. It's thus important to have the area checked by a healthcare professional immediately to examine the underlying cause of the problem and ensure proper treatment is given.

On the contrary, some side-effects that may occur do not require medical attention as most of them usually disappear during treatment and as the patient's body copes with the medicine. The doctor should advise patients on varied ways to help prevent and stop the side-effects from taking their toll on patients.

Dosage

5 tuberculin units (TU) of a single test dose of 0.1 mL is the usual standard used for intradermal (Mantoux) testing in patients of all age. Tuberculin is meant for intradermal injection only, and it shouldn't be injected intramuscularly, intravenously, or subcutaneously—otherwise the test wouldn't give a clear diagnosis.

Therefore before use, the skin area should be inspected first for any extraneous particulate matter, like skin discoloration. If such a condition exists, the physician should not administer the drug. Otherwise, a separate needle and syringe should be used for each injection when everything is in check.

Below is a PPD tuberculin test procedure that's usually performed in patients.

  1. The most suitable area to initiate the test is the volar aspect of the forearm. Areas where the skin is swollen or red, and where a person's veins are visible should be avoided at all times.
  2. Clean the skin area with a suitable germicide and wait for the surface to dry before injecting the antigen into the skin.
  3. Provide the test dose (0.1 mL) of tuberculin with a 1 mL syringe calibrated in tenths initials and fitted with a short, 1/4 to 1/2 inch, 26 or 27 gauge needle.
  4. Clean the stopper of the vial with a viable germicide and leave the site to dry before needle injection. Inject the needle through the stopper and pull about 0.1 mL of tuberculin into the syringe. Be careful not to suck excess air with the removal of each dose because this can over pressurize the vial and may cause leakage at the puncture area.
  5. Dig the point of the needle into the most superficial layers of the skin, with the needle bevel pointing upward and render the dose by intradermal injection. If everything goes smoothly, a definite pale bleb will rise at the needlepoint about 10mm 3/8" in diameter. The bleb will eventually clear after a few minutes, and be sure not to dress the injected skin surface.
  6. Some traces of blood may appear at the administration area following injection. Blot the skin area lightly to banish the blood, though avoid squeezing out the injected tuberculin test fluid.

In scenarios where an improperly rendered injection occurs, another test should be carried out on another skin area immediately at least 2 inches from the first location. The second injection point should be circled or marked as the new area to be read. Reading of the test should always be performed by a trained health professional; hence patients should seek such matters with their physician as self-reading may be subject to errors.

Drug interactions

Although certain drugs shouldn't be used together at all, sometimes two different medicines may be used simultaneously even if an interaction may occur. Under such circumstances, the doctor may suggest a change of the dose or other precautions that he or she deems fit. Patients should, therefore, tell their doctor if they're taking any other prescription or over-the-counter drugs in order to avoid these problems.

Also, certain medicines shouldn't be used during or around the time of eating food, or when eating certain types of food because it's easy for interactions to occur. Mixing tobacco and alcohol with certain drugs may also cause interaction in patients. It's thus pivotal for patients to discuss such matters with their healthcare professional about the use of certain medicines together with food, tobacco, or alcohol. Other health problems that may suppress the diagnostic test include severe skin burns or eczema, tuberculosis, organ transplant, HIV infection or AIDS, and a weak immune system.

Some virus vaccines devised against measles, rubella, mumps, oral polio, varicella, and yellow fever may also stop tuberculin from reacting in patients. Where tuberculin screening is needed at the same time as a measles-containing vaccine or another parenteral attenuated virus vaccine, simultaneous application of the vaccine and tuberculin at different areas is considered the most viable option.

Warnings

Some occasions of allergic reactions may occur in some patients following the use of tuberculin, even in those with no prior history of hypersensitivity. Some allergic reactions, like anaphylaxis, resulting from the drug may occur in a patient. Anaphylaxis is sometimes life-threatening and hence requires fast medical care. Patients should call the doctor immediately if they get a rash or start itching. Or when they experience difficulty breathing and in swallowing food, or when they encounter any swelling of hands, mouth, or face from the medicine.

False negative or positive tuberculin skin test reaction may develop in some patients, particularly those vaccinated against tuberculosis and those exposed to various mycobacteria. Patients should make their doctor aware of any drug they might be using that weakens their immune system, such as a steroid or cancer treatment. In fact, tuberculin skin test shouldn't be provided within one month to patients who either receive or have received live vaccines. These vaccines consist of mumps, measles, oral polio, rubella, varicella, and yellow fever.

Syncope (fainting) may also occur following the administration of injectable medicines, such as tuberculin. A patient may experience episodes of muscle weakness, lightheadedness, or subsequent seizures. Hence proper measures should be in place to avoid falling injury and to restore lost cerebral perfusion after a syncope incidence.

Most importantly, epinephrine injection and other appropriate agents must be available at all times to mitigate the allergic reactions immediately when they occur in patients.

Storage and handling

  • PPD solution must be stored at room temperature or stay refrigerated between 36°â€“ 46° F.
  • Be careful not to fluctuate temperature levels, and don't store on the refrigerator door.
  • All syringes should be filled immediately before any administration can occur.
  • Store and transport tuberculin in darkness at all times and avoid exposure to light.
  • Tuberculin testing solution shouldn't be stored together with other vials, like Tdap, which people can easily mistake for PPD.

Summary

In summary, tuberculin purified protein derivative (PPD) is used in a skin test to help diagnose persons who might be exposed to tuberculosis. Tuberculin skin test is performed by injecting PPD into the surface layer of the skin. However, before its administration, the patient's medical history and current health status should be reviewed for possible sensitivity to components of tuberculin. The healthcare professional should also inform patients of the importance to return for the reading of the test, as self-reading may produce vague and inaccurate figures.

The healthcare professional should give the patient a permanent record to help keep track of their health status. The healthcare provider should also store a health professional record of each patient, including a record of their test history. This permanent file should contain details such as the name of the product, manufacturer, dose, date issued, lot number, and the test result in millimeters of induration. Reporting results as positive or negative all the time is not always satisfactory.

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Last Reviewed:
December 24, 2017
Last Updated:
April 05, 2018
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