π©Έ Fresh Frozen Plasma Dose Calculator
Weight-based plasma dosing in seconds.
For informational purposes only, not medical advice. Consult a healthcare professional.
Fresh frozen plasma is dosed 10-15 mL per kg: a 70 kg adult at 12.5 mL/kg needs 875 mL, about 3.5 units (units run ~250 mL each, so order 4). That dose raises clotting factor levels roughly 20-30% of normal. Enter weight for your dose.
How to Use This Calculator
FFP dosing is weight-based because the goal is a predictable rise in factor concentration in the patient's plasma volume. This is a bedside reference for clinicians.
Enter the patient's weight in kg. Use actual body weight for most adults.
Pick the dose level: 10 mL/kg standard, 12.5 mid, 15 for major bleeding or very low factor levels.
Read the mL and the unit count. Blood banks issue whole units (~200-300 mL), so round up to whole units when ordering.
The Dosing Logic
FFP contains all clotting factors at roughly normal plasma concentration, so transfusing 10-15 mL/kg (about 15-20% of plasma volume) predictably lifts factor levels by a similar fraction. That 20-30% rise is usually enough for hemostasis, since most factors need only ~30% of normal to support clotting. Underdosing is the classic error: 1-2 units in an adult barely moves factor levels and wastes the transfusion risk. Give the full weight-based dose or reconsider whether FFP is indicated at all.
Worked Example
70 kg at 12.5 mL/kg: 875 mL, 3.5 units, order 4. At 10 mL/kg: 700 mL, 2.8 units, order 3. At 15 mL/kg: 1,050 mL, 4.2 units, order 5. A 20 kg child at 12.5: 250 mL, exactly 1 unit. I verified the calculator's arithmetic. Note the rounding: blood banks do not split units routinely, so 3.5 units becomes 4 ordered, and the slight overdose is harmless. ABO compatibility matters (AB plasma is the universal donor), and thawing takes 20-30 minutes, so order before you need it in bleeding patients.
When FFP Is (and Is Not) Indicated
| Indication | FFP role |
|---|---|
| Massive transfusion / trauma | Yes, in balanced ratios with RBCs and platelets |
| Warfarin reversal with bleeding | PCC preferred; FFP if PCC unavailable |
| Factor deficiency, no concentrate available | Yes (e.g. factor V deficiency) |
| Liver disease, pre-procedure | Usually not: corrects numbers briefly, not bleeding risk; use clinical judgment |
| Volume expansion / nutrition | Never: risks without benefit |
| Isolated prolonged INR, no bleeding | Not indicated |
The Choosing Wisely message is clear: FFP is for bleeding or high-risk procedures with coagulopathy, not for numbers alone. INR corrects only transiently because factors clear within hours, so "fixing the INR" before a procedure in liver disease is mostly theater. Prothrombin complex concentrate reverses warfarin faster with less volume. For related transfusion-adjacent math, our HCT/Hgb converter reads the red cell side, and our GFR calculator matters because volume-overloaded kidneys change the risk calculus.
Risks to Respect
TRALI (transfusion-related acute lung injury) is the leading cause of transfusion mortality and presents as sudden hypoxia within 6 hours; TACO (circulatory overload) hits volume-sensitive patients, which is why the mL/kg dose doubles as a volume warning in heart failure and kidney disease. Allergic reactions are common and usually mild; anaphylaxis is rare. Citrate in large volumes chelates calcium: watch ionized calcium in massive transfusion. These risks are why underdosed, indication-free FFP is all downside: the patient gets the risk without the factor rise.
Logistics That Matter
FFP must be ABO-compatible and is thawed on demand (20-30 minutes); once thawed it keeps 24 hours (or 5 days as "thawed plasma" with slightly lower factor VIII). In massive bleeding, most centers switch to pre-thawed universal AB plasma to skip the wait. Document the indication, consent, and unit numbers per local protocol. And recheck coagulation studies after the dose: the goal is clinical hemostasis, and labs confirm the factor rise when bleeding continues.
FFP, Warfarin, and the INR Trap
The most common misuse of FFP is chasing an INR number. In liver disease, the INR reflects failed synthetic function, not bleeding risk, and FFP corrects it for only a few hours while adding volume and TRALI risk; guidelines now discourage pre-procedure FFP for this purpose. For warfarin reversal with life-threatening bleeding, four-factor PCC plus vitamin K is faster, more complete, and far smaller in volume than the 10-15 mL/kg of plasma. FFP still earns its place when PCC is unavailable, in massive transfusion protocols where balanced resuscitation is the goal, and in factor deficiencies with no concentrate (factor V being the classic). A useful bedside rule: if the patient is not bleeding and not heading imminently to a high-risk procedure, the FFP order probably should not exist. And when bleeding is real, dose it like it matters: the full weight-based dose, ABO-compatible, ordered early enough to account for the 20-30 minute thaw. Document the indication and the unit numbers in the transfusion record, and recheck coagulation studies after the dose when bleeding continues.
For informational purposes only, not medical advice. Consult a healthcare professional.
Frequently Asked Questions
How much FFP should I give?
10-15 mL/kg: 700-1,050 mL for a 70 kg adult (3-4 units of ~250 mL). This raises clotting factors ~20-30% of normal. Underdosing (1-2 units in adults) barely moves factor levels.
How many mL in a unit of FFP?
About 200-300 mL, typically ~250 mL. Unit volumes vary by collection, so the blood bank's label volume is the exact figure for precise dosing.
What does FFP correct?
All clotting factors (it is plasma at normal concentration), so it treats multiple factor deficiencies, dilutional coagulopathy in massive transfusion, and warfarin effect when PCC is unavailable.
When is FFP not indicated?
Volume expansion, nutritional support, isolated prolonged INR without bleeding, and routine pre-procedure 'correction' in liver disease. The risks (TRALI, TACO, allergy) outweigh benefit without a hemostatic indication.
FFP vs PCC for warfarin reversal?
PCC (prothrombin complex concentrate) is preferred: faster, smaller volume, more complete reversal. FFP is the fallback when PCC is unavailable. Vitamin K accompanies both for sustained reversal.
What is TRALI?
Transfusion-related acute lung injury: sudden non-cardiogenic pulmonary edema within 6 hours of transfusion, the leading cause of transfusion-related mortality. Stop the transfusion and support oxygenation.
How fast does FFP work?
Factor levels rise with the infusion; clinical effect is rapid for accessible bleeding. But factors clear within hours, so INR correction is transient: treat the patient, not the number.
Does FFP need to be crossmatched?
It must be ABO-compatible (AB is the universal plasma donor) but does not require full crossmatch. Rh is less critical for plasma but local policy varies.
How long does thawed FFP last?
24 hours as FFP (factor VIII declines after), or up to 5 days labeled as thawed plasma with slightly reduced factor VIII. Thawing takes 20-30 minutes; order ahead in bleeding patients.
Can FFP cause volume overload?
Yes: TACO (transfusion-associated circulatory overload) is a real risk, especially in heart failure, kidney disease, and the elderly. The mL/kg dose is also a volume warning; infuse slowly in at-risk patients.