Community pharmacy-based TB skin testing Handout

ISU KDHS Spring CE Seminar 2018

High risk:

•Close contacts of person known or suspected to have active TB

•Foreign-born persons from areas where TB is common

•Persons who visit TB-prevalent countries

•Residents and employees of high-risk congregate settings

•Health care workers (HCWs) who serve high-risk clients

•Populations defined locally as having increased incidence of latent M. tuberculosis infection or TB disease, such as medically underserved, low-income persons who abuse drugs or alcohol

•Children and adolescents exposed to adults at increased risk for infection or disease

Person with LTBI (Infected) / Person with TB Disease (Infectious)
Has a small amount of TB bacteria in his/her body that are alive, but inactive / Has a large amount of active TB bacteria in his/her body
Cannot spread TB bacteria to others / May spread TB bacteria to others
Does not feel sick, but may become sick if the bacteria become active in his/her body / May feel sick and may have symptoms such as a cough, fever, and/or weight loss
Usually has a TB skin test or TB blood test reaction indicating TB infection / Usually has a TB skin test or TB blood test reaction indicating TB infection
Radiograph is typically normal / Radiograph may be abnormal
Sputum smears and cultures are negative / Sputum smears and cultures may be positive
Should consider treatment for LTBI to prevent TB disease / Needs treatment for TB disease
Does not require respiratory isolation / May require respiratory isolation
Not a TB case / A TB case

Stepwise procedure for placing the Mantoux skin test

  1. Preparation
  2. Collect supplies
  3. Tuberculin vial, single-dose disposable tuberculin syringe, ruler with mm measurements, 2x2 gauze pads/cotton balls, alcohol swabs, sharps container, patient forms, pen, gloves if you prefer
  4. Tuberculin administered using ¼ - ½ inch, 27-gauge needle with short bevel
  5. Tuberculin should be stored in the refrigerator and be minimally exposed to light
  6. Drug check (first): Confirm vial contains tuberculin you want to use, confirm tuberculin unit strength, confirm vial not expired
  7. Patient education (why test given, what is involved in procedure, when patient should return—make appointment for follow-up), documentation of informed consent
  8. Wash hands
  9. Choose injection site
  10. Setting: Firm, well-lit surface, patient’s arm should be slightly flexed in at elbow
  11. Location on arm: palm-side-up surface of forearm, 2-4 inches below elbow
  12. Examine site: Confirm free from barriers to placing or reading skin test (e.g. sores, scars, veins)
  13. Clean area with alcohol swab
  14. Prepare vial using best practice technique
  15. Draw up 0.1 mL tuberculin solution [need to administer as soon as possible after syringe is filled]
  16. Expel air bubbles and confirm appropriate volume in syringe
  17. Administer Mantoux tuberculin skin test [INTRADERMAL]
  18. Stretch selected area of skin taut (between thumb and forefinger)
  19. With needle bevel facing up and syringe flange parallel to forearm, hold syringe between thumb and forefinger
  20. With needle bevel against patient’s skin, insert it slowly at 5 to 15 degree anglethrough epidermis approximately 3 mm (so entire bevel is covered and lies just under skin
  21. Should be able to see bevel of needle just below skin surface
  22. Release stretched skin and hold syringe in place on forearm with first and middle fingers
  23. Use thumb to press on plunger to slowly inject tuberculin solution
  24. Expect Firm resistance as solution enters skin
  25. Tense, pale wheal 6-10mm in diameter appears over needle bevel
  26. Remove needle without pressing or massaging area
  27. Discard used syringe immediately in sharps container
  28. If drop of blood appears, lightly blot wit 2x2 gauze pad or cotton ball
  29. Confirm wheal is appropriate size (6-10 mm diameter)
  30. If <6mm in diameter, readminister test at least 2 inches from original site
  31. Needle may have been inserted too deeply or an inadequate dose administered
  32. Do not cover site with bandage
  33. Document
  34. Wash hands
  35. Record location of test site on patient form
  36. Confirm date/time for patient return appointment for test interpretation
  37. Return tuberculin vial to fridge
  38. Counsel patient
  39. Mild itching and swelling or irritation may occur as normal reactions
  40. Avoid scratching site and keep clean and dry
  41. Avoid putting creams, lotions, or adhesive bandages on it and avoid rubbing or scrubbing site

Stepwise measurement of TB skin test

  1. Collect supplies
  2. Ruler with mm markings, felt-tipped or other pen appropriate for skin marking, alcohol swab to clean marking, patient forms for documenting results
  3. Locate skin-test site
  4. Induration (hard, dense, raised formation) only should be measured; not always visible so must rely on palpation
  5. With fingers together, touch area lightly with pads of fingertips
  6. Using light, gentle motion, sweep fingertips over forearm surface in a 2-inch diameter in all four directions to locate margins or edges of induration
  7. Measure induration
  8. If present, use a zigzag feather-like touch over the area of induration to outline margins of induration
  9. North-to-south, South-to-north, East-to-west, West-to-east gentle sweeping motions
  10. Ensure no confusion between margin of induration with margin of muscle on forearm
  11. Check: Raise patient’s arm to 45-degree angle and palpate again
  12. Induration margins should still be present
  13. Diameter of induration measured across forearm from thumb side to little side of arm
  14. Mark induration
  15. Hold palm over injection site with fingertips at outer edge of patient’s forearm and without lifting move fingertips towards induration
  16. Rest one fingertip firmly against induration margin border on one side before marking margin with fine dot
  17. Repeat step 4b from other side of patient’s forearm
  18. Re-palpate to confirm induration marked correctly
  19. If margins of induration are irregular, mark and measure the longest diameter across the forearm

Interpreting the TB skin test

Measure induration not erythema

Measurement / Positive in these populations
≥5 /
  • HIV-infected persons
  • Close contacts to an infectious TB case
  • Persons with chest radiographs consistent with prior untreated TB
  • Organ transplant recipients
  • Other immunosuppressed patients (e.g. , those taking the equivalent of > 15 mg/d of prednisone for 1 month or those taking TNF-α antagonists)

≥10 /
  • Recent immigrants
  • Injection drug users
  • Residents or employees of congregate settings
  • Mycobacteriology laboratory personnel
  • Persons with clinical conditions that place them at high risk
  • Children < 4 years; infants, children, and adolescents exposed to adults at high-risk

≥15 mm /
  • Persons with no known risk factors for TB.
–Although skin testing programs should be conducted only among high-risk groups, certain individuals may require TST for employment or school attendance.
–Diagnosis and treatment of LTBI should always be tied to risk assessment.

Example referral form