<s>[INST] Hi i just got my TB test skin yesterday and i took off the bandage the nurse put on the spot last night but now i don't remember where the spot was. My skin did not turn red and i see no changes and I"m suppose to get it read tomorrow but i don't know if they can read it because there was no changes on my arm. [/INST] hii appreciate your concern reading is taken 48 to 72 hour of injectionsince you are not able to seen any reaction or induration it wii be recorded as 'zero'Reaction to the PPD or tuberculin test is suppressed by the following conditions and test would be read a false negativeInfectious mononucleosisLive virus vaccine - The test should not be carried out within 3 weeks of live virus vaccination.SarcoidosisHodgkin's diseaseCorticosteroid therapy/Steroid useMalnutritionImmunological compromisein such a case a second tuberculin test is necessary it should be carried out in the other arm to avoid hypersensitizing  of the skinHope this helps youthanks for using health care magichave a nice day </s>