Quick comparison (unit volumes)
| Blood product | Typical volume per unit* |
|---|---|
| Packed Red Blood Cells (PRBCs) | ~340 mL / unit |
| Platelets | ~60 mL / unit |
| Cryoprecipitate | ~30–40 mL / unit |
| Fresh Frozen Plasma (FFP) | ~225 mL / unit |
| Fibrinogen Concentrate | Powdered vials; reconstituted dose-based |
*Volumes reflect the figures from the uploaded summary poster.
PRBCs (Packed Red Blood Cells)
What they are:
Whole blood that’s been centrifuged to remove most plasma (about 55% of original plasma volume removed), leaving a unit with a hematocrit ~60% (volume % comprised of red cells).
What they do & when to use:
- Restore oxygen-carrying capacity when tissue oxygenation is impaired by acute or chronic anaemia.
- One unit of PRBCs typically raises the hematocrit of a standard adult by ~3%.
At-a-glance: ~340 mL per unit.
Platelets
Storage & handling:
- Stored at room temperature, cannot be frozen, and must be used within 5 days.
How they work:
- Platelets (thrombocytes) adhere at sites of endothelial damage—initially to collagen.
- Adhesion is strengthened by von Willebrand factor (vWF) released from endothelium and platelets, forming additional links with platelet glycoproteins and collagen fibrils.
- Platelets then interact with thrombin and coagulation factors X, Va, VIIa, XI, IX, and prothrombin, driving clot formation through the coagulation cascade.
Expected response:
- In adults, each “six pack” of platelets is expected to increase the platelet count by approximately 30,000–60,000.
At-a-glance: ~60 mL per unit.
Cryoprecipitate
When to use:
- Hypofibrinogenemia, von Willebrand disease, and scenarios needing “fibrin glue.”
What’s inside (concentrated vs FFP):
Cryo is not just FFP in smaller volume; it’s a fraction that concentrates key factors:
- Fibrinogen 150–250 mg (half-life 100–150 h) → converted by thrombin to fibrin to make clot.
- Factor VIII 80–150 U (half-life ~12 h) → interacts with IX to promote clotting.
- vWF 100–150 U (half-life ~24 h) → travels with XIII.
- Factor XIII 50–75 U (half-life 150–300 h) → improves clot stability.
At-a-glance: ~30–40 mL per unit.
Fresh Frozen Plasma (FFP)
What it contains:
All soluble coagulation factors of plasma, including fibrinogen and factors II, V, VII, VIII, IX, X (with V and VIIIemphasized as particularly important in practice).
When to use:
- Multiple factor deficiencies with active bleeding.
- Emergency bleeding problems on warfarin.
Important cautions:
- Not a plasma expander.
- FFP has an INR ~1.6 and cannot reduce INR below ~1.7 on its own.
How clotting ties together (concept check):
- Factor V helps convert prothrombin → thrombin, and thrombin converts fibrinogen → fibrin to form the clot.
- After injury, Factor VIII activates and separates from vWF; active VIIa interacts with IX, feeding the cascade toward clot formation.
At-a-glance: ~225 mL per unit.
Fibrinogen Concentrate
Basics:
- Synthesized in the liver; normal plasma levels ~1.5–4.5 g/L.
- Acute-phase reactant with a half-life 4–7 days.
Where it’s found & what it does:
- Present in FFP, cryo, and as concentrate.
- Thrombin converts fibrinogen → fibrin, creating the clot.
Why clinicians like it:
- Low volume, easy to make up and store, no cross-match needed.
- Often used as powdered vials for reconstitution; typical dosing 30–60 mg/kg.
- Note: Labeled as expensive; while described as unlicensed in the UK at present, it can be used (per the poster).
Putting it all together (bedside cheat sheet)
- Need oxygen-carrying capacity? Choose PRBCs (expect ~3% Hct rise per unit in an average adult).
- Low platelets or platelet dysfunction? Use platelets (room temp storage; 5-day shelf life; six-pack → +30–60k).
- Low fibrinogen or select vWF-related issues? Cryoprecipitate gives high-yield fibrinogen, VIII, vWF, XIII in a tiny volume.
- Multiple factor deficiencies with bleeding or warfarin-related emergencies? FFP (not a volume expander; INR floor ~1.7).
- Targeted fibrinogen repletion with minimal volume and rapid prep? Fibrinogen concentrate (30–60 mg/kg).
FAQs (SEO-friendly)
How much volume is in each blood product unit?
PRBCs ~340 mL; platelets ~60 mL; cryo ~30–40 mL; FFP ~225 mL. Fibrinogen concentrate is vial-based and reconstituted.
Can platelets be frozen?
No. They’re stored at room temperature and must be used within 5 days.
What should I expect after giving a six pack of platelets to an adult?
A platelet count rise of about 30,000–60,000.
Is FFP a plasma expander?
No. It’s for coagulation factor replacement, not for volume expansion.
What’s the quickest way to raise fibrinogen with the least volume?
Fibrinogen concentrate (dose-based vials), with typical dosing of 30–60 mg/kg.