4.2 Platelets, Plasma, and Cryoprecipitated AHF

4.2 Platelets, Plasma, and Cryoprecipitated AHF

Quick Answer: Whole-blood-derived platelets contain ≥ 5.5 × 10^10 platelets; apheresis platelets contain ≥ 3.0 × 10^11. Both store at 20–24 °C with continuous gentle agitation for 5–7 days and require an FDA bacterial-risk strategy (LVDS, primary-plus-secondary culture/rapid test, or pathogen reduction). FFP is frozen within 8 hours; PF24 within 24 hours. After thaw, the product is FFP for 24 hours at 1–6 °C and may then be relabeled thawed plasma through day 5. Cryoprecipitated AHF is the cold-insoluble precipitate of FFP and contains fibrinogen, Factor VIII, vWF, Factor XIII, and fibronectin. QC is ≥ 80 IU FVIII (FDA monthly average) and ≥ 150 mg fibrinogen (AABB). Store frozen at ≤ −18 °C for 12 months; after thaw hold at room temperature — 6 hours single closed, 4 hours pooled open.

Chapter 3 already covered anticoagulants, transport, and the QC sample plan. This section is the I.D. product identity: how each hemostatic component is made, what is in the bag, and which clock starts when the freezer door opens.

Whole-blood-derived versus apheresis platelets

A whole-blood platelet concentrate is made by the platelet-rich-plasma method or the buffy-coat method from one donation. 21 CFR 640.24 requires ≥ 5.5 × 10^10 platelets in at least 75% of units tested. That unit is a fraction of an adult dose. An adult therapeutic dose is a pool of about 4–6 whole-blood concentrates, which is why a pool and a single apheresis unit can be used interchangeably at the bedside.

Apheresis platelets are collected from one donor as a full adult dose. AABB requires ≥ 3.0 × 10^11 platelets in 90% of sampled units. High-yield collections may be split into two labeled adult doses if each split still meets 3.0 × 10^11. Do not apply the 5.5 × 10^10 number to an apheresis bag or the 3.0 × 10^11 number to a single whole-blood concentrate.

Both products store at 20–24 °C with continuous gentle agitation. Room temperature preserves discoid shape and gas exchange through the bag. Agitation keeps platelets in suspension and supports that gas exchange. Refrigeration of conventional room-temperature platelets produces the cold-storage lesion; granulocyte-style “no agitation” storage is wrong for platelets. Dating is 5 days on a standard container, or 7 days only when both the container and the bacterial-risk strategy are approved for 7-day storage. pH must remain ≥ 6.2 at outdate (Chapter 3.4). A dark, bubbling, or non-swirling bag is an issue-time failure, not a “QC was fine last month” override.

Some U.S. programs issue cold-stored platelets for actively bleeding patients under a specific licensed or variance pathway. That product is not the default 20–24 °C inventory and does not cancel the room-temperature rules on a standard exam stem.

Bacterial risk is part of the platelet definition

Room-temperature, plasma-rich storage is an excellent bacterial culture. FDA’s bacterial-risk-control guidance (December 2020, still the operative 2026 framework) requires every platelet to be issued under an approved strategy. Know the named options:

• Pathogen reduction — the U.S. licensed system is amotosalen plus UVA (INTERCEPT). Treated platelets satisfy the bacterial strategy without a separate culture pathway. Label and dating are product-specific.
• Large-volume delayed sampling (LVDS) — the unit is held, commonly ≥ 36 hours, then a large volume is inoculated into aerobic and anaerobic culture bottles. Depending on the approved protocol and container, dating is 5 or 7 days.
• Primary culture plus a secondary test — an early culture is followed later by a secondary culture or a rapid test (for example a pan-genera detection assay) before issue or to extend dating.

A 7-day date without an approved 7-day container and strategy is a labeling error. Pathogen reduction is not optional trivia; if the stem says INTERCEPT or pathogen-reduced, do not also demand LVDS as if both were required on the same unit.

Plasma — freeze time is the product name

Fresh Frozen Plasma (FFP) is plasma separated and placed at freezer temperature within 8 hours of collection (21 CFR 640.34), or within the shorter timeframe on a specific collection set’s directions. Plasma Frozen Within 24 Hours After Phlebotomy (PF24) is held at 1–6 °C and frozen by 24 hours. PF24RT24 (held at room temperature up to 24 hours, then frozen) exists as a licensed manufacturing variant; the exam trio is still FFP, PF24, and thawed plasma.

Once frozen, FFP and PF24 store at ≤ −18 °C for 12 months. Some facilities store FFP at ≤ −65 °C under an approved longer date; do not assume a 7-year date unless the label and procedure say so (Chapter 3.2). PF24 has modestly lower labile Factor VIII (and some Factor V) than FFP frozen at 8 hours, but both are used as a source of plasma coagulation factors once thawed. Neither is a platelet dose. Neither is cryoprecipitate.

Thaw in a 30–37 °C water bath or approved microwave/thawing device, then store at 1–6 °C. For the first 24 hours the product may still be labeled and issued as thawed FFP or thawed PF24. After 24 hours it may be relabeled Thawed Plasma and kept at 1–6 °C through day 5 from the thaw. Thawed plasma has further decay of labile factors; it remains a volume-and-factor product for many bleeding protocols. Liquid Plasma is never frozen; it is stored at 1–6 °C and dated from the parent whole-blood expiration (commonly 5 days after the whole-blood outdate). Do not call liquid plasma “thawed plasma.”

Pathogen-reduced plasma (INTERCEPT plasma; solvent-detergent pooled plasma such as Octaplas) is labeled and dated by the manufacturer’s circular. Treat those dating and pooling rules as product-specific. Do not overwrite them with the generic 8-hour/5-day story if the stem names the licensed product.

Cryoprecipitated AHF

Cryoprecipitate is made from FFP that is thawed at 1–6 °C. The cold-insoluble precipitate is collected and refrozen. What stays in the precipitate is a short, high-yield list: fibrinogen, Factor VIII, von Willebrand factor, Factor XIII, and fibronectin. What does not stay in useful amount is the rest of the plasma proteome — antithrombin, protein C, protein S, ADAMTS13 as a TTP dose, and the vitamin-K-dependent factors as a warfarin-reversal dose. Cryo is not “small FFP.”

Official potency, repeated here because the exam swaps the numbers (Chapter 3.4):

• 21 CFR 640.56: monthly average of at least four containers ≥ 80 IU Factor VIII.
• AABB / Circular: manufacturing method yields ≥ 150 mg fibrinogen and 80 IU Factor VIII per unit.

Fibrinogen is 150 mg. Factor VIII is 80 IU. There is no official 150 IU Factor VIII specification.

Frozen cryo stores at ≤ −18 °C for 12 months. Thaw at 30–37 °C, then hold at 20–24 °C — do not refrigerate thawed cryo. A single closed unit expires 6 hours after thaw. If units are pooled in an open system, dating becomes 4 hours from that open pooling. An adult fibrinogen dose is typically a pool of about five units (~750 mg or more if each unit meets 150 mg). Pathogen-reduced cryoprecipitated fibrinogen complex (INTERCEPT fibrinogen complex) is an FDA-licensed U.S. product with product-specific thaw dating that may be longer than the conventional 6-hour/4-hour pair. If the stem names that product, follow its circular, not the generic cryo clock.

Worked scenario. FFP is thawed at 09:00 Monday. Until 09:00 Tuesday it is thawed FFP at 1–6 °C. At 10:00 Tuesday it is relabeled thawed plasma and may be kept until 09:00 Saturday. A single cryo unit thawed at 09:00 the same Monday expires at 15:00 that day at room temperature; if it is open-pooled at 11:00, the pool expires at 15:00 (4 hours from pooling), not 15:00 Tuesday.

Exam traps. 5.5 × 10^10 is whole-blood; 3.0 × 10^11 is apheresis. Platelets agitate at 20–24 °C; they are not stored at 1–6 °C. FFP is 8 hours to freezer, PF24 is 24 hours. Cryo Factor VIII is 80 IU, fibrinogen is 150 mg. Thawed cryo is room temperature, 6 hours single / 4 hours pooled open — not 5-day thawed plasma.