Tuberculin »Tuberculin conforms to the regulations of the FDAconcerning biologics (650.10to 650.15)(see Biologics á1041ñ).It is a sterile solution derived from the concentrated,soluble products of growth of the tubercle bacillus (Mycobacterium tuberculosisor Mycobacterium bovis)prepared in a special medium.It is provided either as Old Tuberculin,a culture filtrate adjusted to the standard potency based on the U.S.Standard Tuberculin,Old,by addition of glycerin and isotonic sodium chloride solution,or as Purified Protein Derivative (PPD),a further purified protein fraction standardized with the U.S.Standard Tuberculin,Purified Protein Derivative.It has a potency,tested by comparison with the corresponding U.S.Standard Tuberculin,on intradermal injection of sensitized guinea pigs,of between 80percent and 120percent of that stated on the label.It is free from viable Mycobacteriaas shown by injection into guinea pigs. Packaging and storage— Preserve at a temperature between 2and 8.Multiple-puncture devices may be stored at a temperature not exceeding 30. Expiration date— The expiration date of concentrated Old Tuberculin containing 50%of glycerin is not later than 5years after date of issue from manufacturer's cold storage (5,1year;or 0,2years).The expiration date of diluted Old Tuberculin is not later than 1year after date of issue from manufacturer's cold storage (5,1year;or 0,2years).The expiration date of concentrated PPDcontaining 50%of glycerin is not later than 2years after date of issue from manufacturer's cold storage (5,1year).The expiration date of diluted PPDis not later than 1year after date of issue by the manufacturer.The expiration date of Old Tuberculin and PPDdried on multiple-puncture devices is not later than 2years after date of issue from manufacturer's cold storage (30,1year),provided the recommended storage is at a temperature not exceeding 30. Auxiliary Information— Staff Liaison:Tina S.Morris,Ph.D.,Senior Scientist Expert Committee:(BNT)Biotechnology and Natural Therapeutics/Diagnostics USP28–NF23Page 2000 Phone Number:1-301-816-8397