How One Donation Becomes Four Products
A single unit of donated whole blood is rarely transfused as-is. It is spun and separated so that each patient receives only the component they need — red cells for oxygen delivery, platelets for a low count, plasma for clotting factors, cryoprecipitate for fibrinogen. This "component therapy" lets one donation help several patients and avoids giving a bleeding patient volume they do not need.
Summarised from standard transfusion-medicine teaching (AABB technical manual; Marino, The ICU Book 5th Ed).Component therapy means matching the product to the problem — anaemia → red cells, low platelets → platelets, factor deficiency/bleeding → FFP, low fibrinogen → cryoprecipitate. Whole blood is reserved for special situations (e.g. low-titre O whole blood in major trauma).
What Each One Is, Contains & Does
🔴 Packed red cells (PRBC)
Contains: concentrated red cells (Hct ~55–65%), little plasma. Made by: removing plasma from whole blood. Does: restores oxygen-carrying capacity — 1 unit ↑ Hb ~10 g/L. Store: 2–6 °C, up to ~35–42 days.
🟡 Platelets (RDP / SDP)
Contains: platelets in plasma. Made by: pooling buffy coats from 4–6 donors (RDP) or apheresis from one donor (SDP = 1 adult dose). Does: 1 adult dose ↑ count ~20–40 ×10⁹/L. Store: 20–24 °C with agitation, ~5–7 days.
🔵 Fresh frozen plasma (FFP)
Contains: all coagulation factors, fibrinogen, albumin. Made by: freezing plasma within 8 h of donation. Does: replaces clotting factors — dose ~12–15 mL/kg. Store: frozen ≤ –25 °C ~1 year; use within 24 h once thawed.
⚪ Cryoprecipitate
Contains: fibrinogen, factor VIII, XIII, vWF. Made by: controlled thaw of FFP → cold-insoluble fraction. Does: concentrated fibrinogen replacement. Store: frozen ~1 year. (Fibrinogen concentrate is a factory-made alternative.)
🩸 Whole blood
Contains: everything — red cells, plasma, platelets (function declines with storage). Does: single-product resuscitation. Use: low-titre O whole blood (LTOWB) in major haemorrhage where available; exchange transfusion.
💧 Related products
Fibrinogen concentrate (2–4 g, rapid, pathogen-reduced), prothrombin complex concentrate (PCC) for warfarin/factor reversal, and albumin — used for specific indications rather than volume.
Blood Products — Contains · Made · Dose · Uses · Risks
| Product | What it contains | How it's made | Dose & effect | When to use | Main side effects |
|---|---|---|---|---|---|
| Whole blood | Red cells + plasma + platelets (all-in-one) | Donation ~450 mL + anticoagulant; not separated | 1 unit ~450–500 mL; ↑Hb + volume + factors | Major trauma (LTOWB), exchange transfusion | Volume overload; stored platelets/factors less active |
| Packed red cells (PRBC) | Concentrated red cells (Hct 55–65%) | Plasma removed after centrifugation (± SAGM) | 1 unit ↑ Hb ~10 g/L; give over ≤4 h | Symptomatic anaemia; Hb <70 (<80 if cardiac); bleeding | Febrile/allergic/haemolytic reactions, TACO, TRALI, iron overload, hyperkalaemia (old units) |
| Platelets — RDP (random donor) | Platelets in plasma (1 unit ~5.5 ×10¹⁰) | Buffy coat/PRP from whole blood; pool 4–6 | Pool of 4–6 = 1 adult dose ↑ ~20–40 ×10⁹/L | Thrombocytopenia with bleeding; prophylaxis if very low | Sepsis risk (room-temp storage), febrile/allergic reactions, refractoriness |
| Platelets — SDP (apheresis) | Platelets from one donor (~1 adult dose) | Apheresis — single donor | 1 unit = 1 adult dose ↑ ~30–40 ×10⁹/L | As RDP; fewer donor exposures; for refractory/matched needs | As platelets; costlier; same infective/immune risks |
| Fresh frozen plasma (FFP) | All clotting factors, fibrinogen, albumin | Plasma frozen ≤ –25 °C within 8 h | ~12–15 mL/kg; corrects PT/APTT | Multi-factor deficiency + bleeding; MTP; DIC; warfarin (if no PCC) | TACO (volume), TRALI, allergic reactions; ABO-compatible needed |
| Cryoprecipitate | Fibrinogen, factor VIII, XIII, vWF | Cold-insoluble precipitate from thawing FFP | ~1 pool (5 units) ↑ fibrinogen ~0.5–1 g/L | Fibrinogen <1.5 (<2 obstetric) g/L; DIC; major haemorrhage | Allergic/febrile reactions; infection risk (pooled) |
| Fibrinogen concentrate | Purified, pathogen-reduced fibrinogen | Fractionated from pooled plasma (manufactured) | 2–4 g; rapid, standardised dose | Hypofibrinogenaemia; alternative to cryoprecipitate | Thrombosis (over-dose); cost/availability |
Exact volumes, additive solutions and shelf-lives vary by centre and national standards — always follow your own blood bank's labelling.
When To Transfuse — the Restrictive Approach
- Platelets: keep >50 ×10⁹/L for surgery/bleeding (>100 for CNS/eye or major/ongoing haemorrhage); prophylaxis often at <10 ×10⁹/L.
- FFP: for bleeding + PT/APTT >1.5× normal, or in the MTP.
- Fibrinogen: keep >1.5 g/L (>2 g/L in obstetric haemorrhage) with cryoprecipitate/concentrate.
Random-donor platelets (RDP) and whole blood are the mainstay in many Indian blood banks; apheresis platelets (SDP) and fibrinogen concentrate may be limited to larger centres. Pre-operative iron-deficiency anaemia is very common — optimise with iron in clinic rather than transfusing on the table (Patient Blood Management). Transfusion practice is governed by the National Blood Transfusion Council (NBTC) and Drugs & Cosmetics rules; consent, ABO/Rh grouping and cross-match, and haemovigilance reporting are mandatory. Always send a group & save / cross-match early when bleeding is anticipated.
Transfusion Reactions — Recognise Fast
Delayed hazards: delayed haemolysis, transfusion-transmitted infection, iron overload, and TA-GvHD (use irradiated components in at-risk patients). For DIC, coagulopathy reversal and the ICU picture, see Transfusion & Coagulopathy in the ICU →
Common Mistakes with Blood Products
The commonest cause of a fatal ABO haemolytic reaction is mis-identification of patient, sample or unit. Rigorous bedside checking is the single most important safety step.
Transfuse one unit and reassess; liberal triggers add risk without benefit in stable patients.
FFP is for bleeding with multi-factor deficiency or the MTP — not for volume, and not to "correct" a mildly raised INR before a low-risk procedure.
Citrate chelates calcium → ionised hypocalcaemia impairs clotting and cardiac function; monitor and replace.
TACO is circulatory overload (treat with diuresis); TRALI is immune non-cardiogenic oedema within 6 h (supportive care). Management differs.
Immunocompromised/at-risk patients need irradiated cellular components to prevent transfusion-associated graft-versus-host disease.
Exam Pearls
Q: How much does 1 unit of PRBC raise the haemoglobin?
~10 g/L (about 1 g/dL) in an average adult.
Q: What does cryoprecipitate contain?
Fibrinogen, factor VIII, factor XIII and von Willebrand factor — the cold-insoluble precipitate from thawing FFP.
Q: RDP vs SDP?
RDP = random-donor platelets pooled from 4–6 whole-blood donors (1 pool ≈ 1 adult dose); SDP = single-donor apheresis platelets (1 unit ≈ 1 adult dose, fewer donor exposures). Both raise the count ~20–40 ×10⁹/L.
Q: Restrictive red-cell transfusion threshold?
Hb <70 g/L (target 70–90); <80 g/L for cardiac disease/ACS or symptoms — single-unit transfusions with reassessment (TRICC/TRISS).
Q: Platelet targets for surgery?
>50 ×10⁹/L for most surgery/bleeding, >100 for CNS/eye or major ongoing haemorrhage; prophylactic transfusion often at <10 ×10⁹/L.
Q: How is FFP made and stored?
Plasma frozen to ≤ –25 °C within 8 h of donation; stored ~1 year; used within 24 h of thawing. Dose ~12–15 mL/kg.
Q: TACO vs TRALI?
TACO = circulatory overload (hypertension, raised JVP, cardiogenic oedema → diuresis). TRALI = immune non-cardiogenic pulmonary oedema within 6 h with normal filling pressures → supportive care.
Q: Which reaction is the most lethal, and its cause?
Acute haemolytic reaction from ABO incompatibility — almost always a bedside identification/clerical error.
References
- AABB. Technical Manual & Standards for Blood Banks and Transfusion Services (current edition).
- Carson JL, Stanworth SJ, Dennis JA, et al. Transfusion thresholds for guiding red blood cell transfusion (Cochrane / AABB guidance).
- Hébert PC, Wells G, Blajchman MA, et al. (TRICC). A multicentre, randomised, controlled clinical trial of transfusion requirements in critical care. N Engl J Med. 1999;340:409–417.
- Holst LB, Haase N, Wetterslev J, et al. (TRISS). Lower versus Higher Hemoglobin Threshold for Transfusion in Septic Shock. N Engl J Med. 2014;371:1381–1391.
- Marino PL. The ICU Book, 5th Edition. Transfusion Therapy / Blood Components. Wolters Kluwer; 2025.
- National Blood Transfusion Council (NBTC), India. Standards & guidelines for blood transfusion services.
- Washington Manual of Critical Care, 4th Edition. Kollef MH, Witt CA (eds). Transfusion. Wolters Kluwer; 2023.