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 false negative skin test can occur if a live vaccine, such as MMR, is given BEFORE the TB skin test is done. If MMR vaccine is given, you should wait at least 4 weeks before doing the TB skin test. All vaccines, live or inactivated, can be given on the same day or at any time AFTER a TB skin test is done.