C.B.
Hi A.! I do this for a living :) She should have a lump where the shot is given that goes away about 20min after it is given. It needs to be "read" 48-96 hours later. When it is read they are looking for an induration or lump not the redness that may be there. If the lump is below 5mm in a person 4 years and older it is negative. If the lump is between 5-9mm in a person 4 years and older it is questionable and needs to be repeated. If it is 10mm or larger it is a positive result and chect x-rays need to be taken.
The repeat can be done at anytime unless she had a live vaccine at the same time as hte TB test such as Varicella or MMR. If that is the case she has to wait 4-8weeks to be re-tested because they can be given on the same day but after that they need to sepersted.
Hope this helps and get back to me if you have any questions :)
C.