It comes pre-mixed in 1-gallon pails, so the color and consistency is perfect every time. Coverage with a Â¼ grout line is approximately 50 sq. ft. for a 12 x12 application. See chart for additional information regarding grout coverage per gallon.
In brief: 48 to 72 hours. The actual placement of the TB skin test (PPD) only takes a few seconds and should be painless. However you need to return to the clinic to have the skin test read by someone who knows what they are looking for between 48 and 72 hours later. In brief: 48 to 72 hours.
A person's negative TB skin test may mean one or more of the following. 1  Person does not have TB infection. 2  Person got the TB infection within last 10-12 weeks, and the TB skin test cannot detect the TB infection. 3  Person has overwhelming TB disease, and the immune system is not responding.