Products And Components

Component preparation and the separation logic

Component therapy is the principle that a single whole blood donation is fractionated so each patient receives only the part they need. A standard 450-500 mL collection in CPD or CPDA-1 anticoagulant-preservative is processed by differential centrifugation: a light (soft) spin separates packed red blood cells (PRBCs) from platelet-rich plasma (PRP), and a heavy (hard) spin of the PRP yields a platelet concentrate plus fresh frozen plasma (FFP). This is high-yield because MLS items routinely ask which product comes from which spin and at what step a derivative is made.

Cryoprecipitate (cryo) is made by thawing FFP at 1-6 C and collecting the cold-insoluble precipitate. Each bag concentrates fibrinogen (factor I), factor VIII, factor XIII, von Willebrand factor (vWF), and fibronectin. The classic exam trigger for cryo is hypofibrinogenemia (fibrinogen < 100 mg/dL) in disseminated intravascular coagulation, not isolated factor VIII deficiency, which is now treated with recombinant concentrate.

Storage, expiration, and dose

Memorize the storage matrix exactly; questions frequently change one variable to test whether you notice the violation.

Expected response is equally testable. One unit of RBCs raises hemoglobin by ~1 g/dL (hematocrit by ~3%) in a stable, non-bleeding adult. One apheresis platelet (or a pool of 4-6 whole-blood-derived units) raises the platelet count by 30,000-60,000/uL. One unit of FFP supplies ~200-250 mL plasma; the typical dosing target is 10-20 mL/kg.

Anticoagulant-preservatives and the storage lesion

The choice of anticoagulant-preservative sets the outdate, so the exam expects you to connect the additive to the shelf life. Citrate chelates calcium to prevent clotting, phosphate buffers pH, and dextrose fuels glycolysis to maintain ATP. CPDA-1 adds adenine, supporting a 35-day outdate, whereas plain CPD allows only 21 days. Additive solutions (AS-1 Adsol, AS-3 Nutricel, AS-5 Optisol) add saline, adenine, glucose, and sometimes mannitol after most plasma is removed, extending RBC storage to 42 days.

During storage the storage lesion develops: 2,3-DPG falls (shifting the oxygen dissociation curve left), pH drops, plasma potassium rises as cells leak, and ATP declines. This is why irradiated and aged units are a concern for neonates and renal patients, and why a question pairing high plasma potassium with an older unit points to expected storage changes rather than hemolysis from a procedural error.

Common traps and special products

• Irradiated components (target 25 Gy to the midplane) prevent transfusion-associated graft-versus-host disease in immunocompromised recipients, intrauterine transfusions, neonatal exchange, and directed donations from blood relatives. Irradiation accelerates potassium leak, so the RBC outdate is shortened to 28 days from irradiation or the original expiration, whichever is sooner.
• Leukoreduced products contain fewer than 5 x 10^6 residual white cells per unit and reduce febrile nonhemolytic reactions, HLA alloimmunization, and cytomegalovirus transmission; prestorage leukoreduction by filtration is preferred over bedside filters.
• Washed RBCs are saline-rinsed to remove plasma proteins for IgA-deficient patients with anti-IgA or those with repeated severe allergic reactions. Because washing breaches the closed system, the product expires in 24 hours (refrigerated).
• Frozen/deglycerolized RBCs use glycerol cryoprotection for rare units and autologous storage; once deglycerolized the open unit also outdates in 24 hours.
• A frequent distractor: platelets are stored at room temperature, not refrigerated because chilling causes shape change, activation, and rapid hepatic clearance. Another trap swaps the FFP thaw outdate (24 hours at 1-6 C) with the pooled cryoprecipitate outdate (4 hours at room temperature) — keep these distinct.

When you review any component item, ask three things in sequence: what spin or process made it, what is its exact storage temperature and outdate, and what specific clinical deficiency it corrects. That triad — preparation, storage, indication — answers the large majority of product questions on the 100-item, 2-hour-30-minute computer adaptive MLS exam, where Blood Banking carries 17-22% of the weight. Treat each number as a discrete fact to recall instantly under time pressure, because component logistics items reward speed and precision rather than reasoning.

Indication summary you can recite

A final memory aid ties products to clinical triggers so you can answer selection items quickly. Reach for RBCs for symptomatic anemia or acute blood loss; platelets for thrombocytopenia with bleeding or counts under roughly 10,000/uL prophylactically; FFP for multiple coagulation factor deficiencies, warfarin reversal when concentrate is unavailable, or plasma exchange in thrombotic thrombocytopenic purpura; and cryoprecipitate specifically for low fibrinogen, factor XIII deficiency, or uremic bleeding.

When an item describes a single deficient factor with a recombinant product available, the factor concentrate beats plasma or cryo because it carries lower volume and infection risk. Each of these pairings recurs across the Blood Banking domain, so rehearse product-to-indication links alongside the storage and dose numbers until both are automatic.