Guidelines and Techniques of Measurement

NOTE: The results of the skin test must be read by a trained health care worker 48-72 hrsfrom the time the test was administered. (Results reported by applicant, even if “negative” are not acceptable). Positive reading may be detected up to 7 days later, but re-administration is highly recommended if there is no induration or induration is too small to be interpreted as positive

Supplies/Necessities

•Artificial arm(s)

•Mantoux Tuberculin Skin Test Record form

•Small (6"), flexible ruler, preferably clear plastic with mm (and not inch) increments

•Ball point pen or eyeliner pencil

•Eye make-up remover or baby oil to remove marks

•Patient education materials

•Since you will be using the tips of your fingers to palpate, make sure your fingernails are shorter than your fingertips (you should not be able to see them when viewing palm side of hand)

•Use well-lit area

Introduction

•Verify that you have correct patient

•Introduce self to patient

•Explain procedure

•Wash hands

•Make patient at ease, arm in relaxed position

Inspect for site

•Verify from record which arm received skin test

•Inspect for the site of injection

Palpate: finding the margin ridge (if any)

•Palpate with arm bent at elbow 90 degrees

•Lightly sweep 2" diameter from injection site(4 directions)

•Use zig-zag feather-light touch

•Repeat palpation with arm bent at elbow 45 degrees

Mark: placing marks

•Hold your palm over injection site

•Place your finger pad onto patient’s arm and move it toward injection site

•Drop fingernail on skin before marking

•Place single dot on skin at fingernail, left

•Place single dot on skin at fingernail, right

•Inspect dots, repeat finger movements towards site, adjust dots

•Make sure dots are transverse to long axis of arm

Measurement: placing and reading ruler

•Place the “zero” ruler line inside left dot edge

•Read the ruler line inside the right dot edge

•If unsure, ask a co-worker to assist you

•If still unsure, repeat the skin test immediately on either arm. Using the same arm does not affect skin test results, however, repeat test 2 inches from the patient’s arm after reading

Measurement

•Measure the induration (raised, hardened area) NOT the erythema (redness) or bruise - distinguish the difference

•Feel with your fingertips; do NOT measure just what you see (often the induration is not clear enough to see)

•Measure the diameter of the induration transversely to the long axis of the arm

•Use a ball point pen to mark the edges of induration (ask permission of the patient). Hold pen lightly and roll the point towards the edge until you feel resistance; repeat on the opposite side of the induration and measure between the two points using tuberculin skin testing ruler or a ruler with mm (not inches) increments

Recording

•Note in patient’s medical record when the skin test was administered

•Record the measurement in millimeters of induration (interpretation of reading will vary depending on individual patient)

NOTE: Reading that is recorded as only “positive” or “negative” is unacceptable and may result in the patient having to repeat a skin test

•Record who read the skin test

•Record date and time of reading

•Record presence/absence of ulcerations, necrosis, blistering, etc.

Follow-up

•Know interpretation guidelines for your facility

•Direct patient for follow-up (e.g., chest x-ray if skin test result is positive)

Education

•Explain that a positive skin test result means latent infection with the TB germ

•Explain what a negative skin test result means

•Provide appropriate written materials and documentation

•Answer patient questions