Tuberculin, Purified Protein Derivative (PPD)

A to Z Drug Facts

 Action Contains soluble products from mycobacterium, which react with lymphocytes to release mediators of cellular hypersensitivity. Some of these mediators induce inflammatory response. Positive reaction is consistent with previous or current tuberculosis infection or previous BCG vaccination.

 Indications Detection of delayed hypersensitivity to Mycobacterium tuberculosis; aid in diagnosis of infection with M. tuberculosis; routine testing for tuberculosis; testing individuals suspected of having contact with active tuberculosis; follow-up verification testing in individuals who have had reactions to tuberculin multipuncture devices used as screening test.

 Contraindications Persons known to be tuberculin-positive reactors.

 Route/Dosage

ADULTS & CHILDREN: Intradermal 0.1 ml of 5 TU/0.1 ml concentration (Mantoux test) or multiple puncture device. HIGHLY SENSITIZED PERSONS: Intradermal 0.1 ml of 1 TU/0.1 ml concentration. INDIVIDUALS WHO FAIL TO REACT TO PREVIOUS INJECTION OF 5 TU: Intradermal 0.1 ml of 250 TU/0.1 ml concentration.

Routine Tuberculin Screening

CHILDREN: Perform at 12 mo, 4–6 yr and 14–16 yr.

 Interactions

BCG vaccine, previous: May result in positive PPD test (see Precautions). Corticosteroids or other immunosuppressive drugs: May suppress reactivity to any tuberculin test. Recent immunization with live virus vaccines (including influenza, measles, mumps, rubella, polio virus, smallpox, yellow fever): May suppress reactivity to any tuberculin test. If tuberculin skin testing is indicated, perform it either before or simultaneous with immunization or 4 to 6 wk after immunization.

 Lab Test Interferences None well documented.

 Adverse Reactions

DERM: Immediate erythematous reactions, vesiculation, pain, ulceration, necrosis or scarring at administration site; bleeding at puncture site (tine test).

 Precautions

Pregnancy: Category C. Use if needed. Unrecognized tuberculosis places infant in grave danger of tuberculosis and tuberculous meningitis. No adverse effects on fetus from tuberculin have been reported. Lactation: Undetermined. Children: A child who has been exposed to tuberculosis must not be judged free of infection until there is negative tuberculin reaction at least 10 wk after ending contact with tuberculous person. Elderly patients: Skin-test responsiveness may be delayed or reduced in magnitude among older persons. Two-step testing is especially important in persons ³ 35 yr. Reactions may peak after 72 hr. BCG vaccine: Persons previously immunized with BCG vaccine may test positive to tuberculin skin test. Tuberculin reactions caused by BCG cannot reliably be distinguished from reactions caused by natural mycobacterial infections. Tuberculin reactivity in BCG vaccinees does not reliably predict protection against M. tuberculosis. Bioequivalency: The various PPD solutions are generically equivalent but differ from PPD multipuncture devices and from old tuberculin (OT) products. Immunodeficiency: Skin-test responsiveness may be suppressed during or for as much as 6 wk after viral infection, live viral vaccination, miliary or pulmonary tuberculosis infection, bacterial infection, severe febrile illness, malnutrition, sarcoidosis, malignancy or immunosuppression (eg, corticosteroids or other immunosuppressive pharmacotherapy). In most patients who are very sick with tuberculosis, a previously negative tuberculin test becomes positive after a few weeks of chemotherapy. Interpretation of test results: Positive PPD reaction indicates hypersensitivity to tuberculin and implies past or present infection with M. tuberculosis. Positive reactions do not necessarily signify active disease. Further diagnostic procedures (g, chest radiograph, microbiological examination of sputum) must be conducted before a diagnosis of tuberculosis can be made. Multipuncture devices: Multipuncture devices are screening tools that aid in determining tuberculin hypersensitivity. They may contain either PPD or OT. These devices are comparable to 5 TU of PPD but may yield false-positive reactions because quantity of tuberculin deposited into skin cannot be precisely controlled. Positive reactions to multipuncture devices must be confirmed with intradermal injection of PPD solution. OT cross-reacts with other mycobacteria (eg, Mycobacterium avium). Multipuncture devices are useful in persons who object to use of needle and syringe (eg, children). Repeated testing of uninfected individuals: Does not sensitize to tuberculin.

 Administration/Storage

• Cleanse site with 70% isopropyl alcohol, acetone, ether or soap and water and allow to dry before test injection.
• Avoid areas with rash, hairy areas, scars, pimples, moles and other marks.
• Use fresh solution for injection.
• For intradermal injection, use 26- or 27-gauge ½-inch needle to administer intradermal injection into flexor or dorsal surface of forearm, creating white bleb 6–10 mm in diameter. No dressing is required.
• For multiple puncture device, apply unit firmly and without twisting to volar surface of upper ¹/₃ of forearm for 1 sec. Make sure all four tines penetrate skin.
• If performing retest, perform on opposite forearm.
• Do not use 250 TU/0.1 ml concentration for initial testing.
• PPD multi-puncture devices should be stored at room temperature.
• PPD solution should be stored in refrigerator.

 Assessment/Interventions

• Obtain patient history, including prior PPD test results, BCG vaccination, drug history and any known allergies. Individuals who may have received BCG vaccination will likely exhibit false-positive reactions.
• Assess appropriate timing of testing; viral febrile illnesses, liver virus vaccination, malnutrition or immunosuppression may suppress results. Tuberculin skin testing cannot be performed until 4–6 wk after immunization with live virus vaccines.
• Obtain history of exposure to tuberculous persons prior to skin testing.
• Assess for hypersensitivity, especially in patients with high risk of disease. Have epinephrine readily available.
• Assess ability of patient to accurately read test results.
• Interpret results 48–72 hr after administration. Delayed hypersensitivity reactions begin within 5–6 hr and peak after 48–72 hr. Reactions in elderly persons and those never before tested may peak sometime after 72 hr.
• Measure induration along transverse diameter at right angle to long axis of forearm.
• Detect induration by gently palpating double skinfold between thumb and forefinger, starting in normal area around test site and moving toward test site until thickened area is felt. Consider only induration in interpreting test. If erythema > 10 mm in diameter occurs without induration, injection may have been made too deeply; retest patient.
• Interpretation
• Induration < 5 mm in diameter are classified as negative. This indicates lack of hypersensitivity to tuberculin and implies that tuberculous infection is highly unlikely.
• Reactions to PPD with induration ³ 5 mm diameter are classified as positive in (1) persons with HIV infection or risk factors for HIV infection (including IV drug use) whose HIV status is unknown, (2) persons with close recent contact with infectious tuberculosis cases and (3) persons with chest radiographs consistent with old healed tuberculosis.
• Induration ³ 10 mm diameter are classified as positive in (1) foreign-born persons from high-prevalence countries in Asia, Africa or Latin America; (2) HIV-negative IV drug users; (3) medically underserved low-income populations (eg, high-risk racial or ethnic minority populations); (4) residents of long-term care facilities (eg, correctional institutions, nursing homes, institutions for disabled persons); (5) persons with conditions that increase risk of tuberculosis (eg, silicosis, gastrectomy, jejunoileal bypass, body weight ³ 10% below ideal weight, chronic renal failure, diabetes mellitus, immunosuppressive therapy, leukemias, lymphomas, or other malignancies); (6) other high-risk populations defined locally.
• Induration ³ 15 mm diameter are classified as positive in all other persons not listed above, especially in persons > 35 yr.
• Reactions to either OT or PPD multipuncture devices with induration ³ 2 mm in diameter or presence of any vesiculation at application site are classified as positive. Positive response indicates hypersensitivity to tuberculin and implies past or present infection with M. tuberculosis. Retesting with PPD solution is necessary in patients who exhibit positive responses (any size induration) to multipuncture devices.
• If patient is BCG positive, use alternative measurement for accuracy of results.
• Apply cold packs or topical corticosteroid preparations to administration site for symptomatic relief of associated pain, pruritus and discomfort.
• If patient is considered at risk for immunodeficiency, PPD should be applied with other skin tests (eg, mumps, candida) to evaluate cell-mediated immunity. Skin tests should be at least 5–10 cm apart.

 Patient/Family Education

• Inform patient to return in 48–72 hr for test interpretation or explain how to interpret skin results. Provide card for interpretation.
• Advise patient of significance of test results and stress importance of reporting results.
• If test results are positive, provide information on where patient can obtain further evaluation.

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Copyright © 2003 Facts and Comparisons
David S. Tatro
A to Z Drug Facts