Vaccination & TB Skin Test - College of Southern Nevada

7) Two Step TST: Administer the test. Read results 48-72 hours later. Minimum 7days after administration of the first
step. Administer step 2. Read results 48-72 hours later.
NOTE: Some healthcare facilities often provide a two step TST as follows. Administer step 1. Seven days later, read
results and administer step 2. Read results 48-72 hours later. This will be accepted by CSN.
8) TST intervals: Steps 1 and 2 must be separated by minimum 7 days between administration dates. The test results must
be evaluated (read) at the healthcare provider facility where the test was administered.
9) Positive TST readings: A TB skin test is considered positive if the resulting diameter of the induration (elevated skin
area, not the area of redness) measures:
a. 10 mm or more for foreign born individuals
b. 15 mm or more for US born individuals
10) Positive TST
See CSN TB Skin Test Policy and/or call CSN Infection Control Manager for details.
a. Written documentation of a positive TB skin test must be provided.
b. NEW positive TB skin test
i. Must be referred to a healthcare provider for an evaluation, chest x-ray (CXR) and/or
treatment/preventive recommendations, if applicable.
ii. Provide the health program with
1. written results of positive TB skin test
2. written CHX report from the radiologist (not the actual x-ray)
3. Completed Tuberculosis Symptom Screening Questionnaire
c. HISTORY positive TST
i. Must provide written documentation of the past positive TB skin test.
1. If documentation of past positive TB skin test student will get one TB skin test to document status.
ii. Must show documentation of clear CXR taken as follow-up to previous positive TB skin test no older
than 2 years
iii. Written documentation of negative CXR indicating no active pulmonary disease
iv. Completed Tuberculosis Symptoms Screening Questionnaire annually.
1. If symptoms suggestive of TB develop an immediate referral to healthcare provider required.*
v. Exempt from further TB skin tests (TB skin test will always result in positive).
12.2011
d. HISTORY positive TB skin test WITH documentation of successfully completing the recommended course
of INH treatment
i. Documentation of successfully completing the recommended course of INH treatment (minimum 6
months)
ii. Complete Tuberculosis Symptom Screening Questionnaire annually.
1. If symptoms suggestive of TB develop an immediate referral to healthcare provider required.*
iii. Exempt from further TST and chest x-rays
* CONFIRMED or SUSPECTED TB INFECTION – CSN Infection Control Manager and Southern Nevada
Health District must be notified immediately.
11) FOREIGN born individuals – Many are given BCG vaccine as a child. BCG interacts with TST resulting in a positive
skin test. This positive TB skin test is often a false positive.
a. Written documentation of a positive TB skin test must be provided.
b. CDC recommends every positive TST be evaluated further with a follow-up chest x-ray (CXR)*, regardless
whether or not there is a history of BCG.
c. Must provide written results of negative (no active pulmonary disease) CXR (not the actual chest x-ray) no
older than 2 years.
d. Future TB skin tests will always test positive.
e. In this case, a student is required to complete a Tuberculosis Symptoms Screening Questionnaire annually
in lieu of a TST.
f. A CHX is good for 2 years.