Packaging and storage— Store platelets in an approved container. Platelets may be stored in plasma or in an approved additive solution at 20 to 24 with continuous gentle agitation for no more than 5 days after date of preparation.

Labeling— Label the container to indicate the collection date, the donation number or other coding means to uniquely identify the unit and to provide traceability to the donor, approximate volume, storage temperature, and its expiration date. Indicate the anticoagulant solution used and any additive solutions added subsequent to collection. Also label the container to identify donor status (for example, volunteer or paid). Label it also with the following statements: “See Circular of Information for the Use of Human Blood and Blood Components for indications, contraindications, cautions, and methods of infusion”; “Properly identify intended recipient”; “This product may transmit infectious agents”; and “Rx only.” In addition, label the container to indicate the product name as indicated in Table 1. [note—The name is determined by the method of platelets preparation (derived from whole blood or by apheresis) and by performing the necessary testing to ensure that the product meets the minimum requirements for the named products, as indicated in Table 1.] [note—Platelets prepared by apheresis should be labeled with the donor's ABO blood group and Rh factors. Test the donor's whole blood or red blood cells as directed under Whole Blood or Red Blood Cells, respectively.]

Identification— Dilute a small volume of Platelets 1:1000 with 0.9% sodium chloride solution. Place a small drop of the diluted platelets onto the end of a clean glass microscope slide. Obtain a second clean glass microscope slide, and draw its edge across the drop of platelets so that capillary action spreads the drop across the first slide. Push the second slide in one smooth motion across the first slide to make a smear of platelets. Allow the smear to dry. Apply a liberal amount (1 to 2 mL) of Wright's stain to the platelet smear, and allow to stand for 2 minutes. Dip the slide in deionized water, and gently blot dry with absorbent paper. Examine the slide using a microscope at 100× with bright illumination. Platelets appear as anuclear round or oval shapes approximately 0.1 to 0.2 µm in diameter, with some fine purple granulation. The platelets may occasionally appear to have a purple center with clear cytoplasm at the periphery.

Platelet count— Use a commercially available, validated hematology analyzer to determine platelet count. Proceed as directed in the instrument's operating manual.

Residual leukocyte count— Place 100 µL of Platelets into a suitable test tube. Add 400 µL of 0.01% (w/v) crystal violet in 15% (v/v) acetic acid, and mix thoroughly. Fit a hemocytometer with a 50-µL counting volume and a bright background with a cover slip. Load the counting chamber with the mixture until the counting area is completely covered, but do not overfill. Cover the counting chamber with a suitable moist lid to prevent evaporation, and allow to settle undisturbed for 10 to 15 minutes. Remove the lid, and place the chamber on the stage of a light microscope fitted with a 10× ocular lens and 20× objective. Count the leukocytes in the entire 50-µL counting volume. Calculate the leukocyte count in the platelets, expressed in leukocytes per µL, by dividing the observed leukocyte count by 10. Calculate the total number of leukocytes in the red blood cell unit as follows:

pH 791 (for stored Platelets)— Transfer aseptically a volume appropriate for the equipment: pH must be greater than 6.2 throughout the storage period.

Topic/Question	Contact	Expert Committee
Monograph	Anita Y. Szajek, Ph.D. Senior Scientist 1-301-816-8325	(BBBBP05) Biologics and Biotechnology - Blood and Blood Products

USP32–NF27 Page 1700