Transfusion Consent Risk Calculator

Evidence-based risk estimates for informed consent discussions

FDA/SHOT/REDS Data Hemovigilance Statistics AABB Standards
Risk Calculator

Risk Calculator

Select Blood Products

Click to select products being transfused:

Red Blood Cells (RBCs)
~300 mL per unit
Platelets
~300 mL (apheresis) or ~50 mL/unit (pooled)
Fresh Frozen Plasma (FFP)
~250 mL per unit
Cryoprecipitate
~15 mL per unit (typically pooled 5-10 units)
Understanding Risk Presentation

Risks are presented as approximate frequencies (e.g., "1 in 1,000") to facilitate patient counseling. Actual rates may vary based on:

  • Patient factors (age, comorbidities, transfusion history)
  • Product modifications (irradiated, washed, leukoreduced)
  • Institutional practices and hemovigilance
Select Blood Products

Choose one or more blood products to see evidence-based risk estimates for adverse transfusion events.

Red Blood Cell Transfusion Risks

Febrile Non-Hemolytic (FNHTR)
Mild

1 in 130

95% CI: 1 in 156 to 1 in 238

Temperature rise >=1C without hemolysis

Fever Chills Rigors
Hendrickson 2016
Allergic (Mild)
Mild

1 in 130

95% CI: 1 in 213 to 1 in 345

Urticarial reaction to plasma proteins

Urticaria Pruritus Flushing
Hendrickson 2016, AABB

TACO
Severe

1 in 200

95% CI: 1 in 100 to 1 in 700

Circulatory overload causing pulmonary edema

Dyspnea Hypertension Pulmonary edema
Delaney 2016, SHOT
TRALI
Life-Threatening

1 in 8,000

95% CI: 1 in 5,000 to 1 in 12,000

Acute lung injury within 6 hours

Acute dyspnea Hypoxemia Bilateral infiltrates
SHOT, Vamvakas 2009
Delayed HTR
Moderate

1 in 7,000

95% CI: 1 in 5,000 to 1 in 11,000

Anamnestic antibody response 3-14 days post-transfusion

Unexpected Hgb drop Jaundice Dark urine
Tormey 2019, AABB

Acute HTR (Non-fatal)
Severe

1 in 40,000

95% CI: 1 in 25,000 to 1 in 76,000

Acute hemolysis from incompatible transfusion

SHOT, AABB
Anaphylaxis
Life-Threatening

1 in 30,000

95% CI: 1 in 20,000 to 1 in 50,000

Severe systemic allergic reaction

SHOT, Delaney 2016
Septic Reaction
Life-Threatening

1 in 350,000

95% CI: 1 in 250,000 to 1 in 500,000

Bacterial contamination (rare for RBCs)

FDA, SHOT

Fatal Acute HTR
Fatal

1 in 1,000,000

95% CI: 1 in 600,000 to 1 in 1,800,000

ABO-incompatible causing fatal intravascular hemolysis

FDA Fatalities, SHOT
TA-GVHD
Fatal (>90%)

< 1 in 1,000,000

95% CI: Near zero to 1 in 1,000,000 (with irradiation)

Prevented by irradiation of cellular products

AABB

Platelet Transfusion Risks

Note: Platelet transfusions carry higher risks of febrile/allergic reactions and sepsis compared to RBCs due to room temperature storage and higher plasma content.
Adverse Event Risk Estimate 95% Credible Interval Severity Key Notes
FNHTR 1 in 20 1 in 10 to 1 in 50 Mild More common than with RBCs
Allergic (Mild) 1 in 50 1 in 30 to 1 in 100 Mild Higher plasma content increases risk
Septic Reaction 1 in 50,000 1 in 25,000 to 1 in 75,000 Life-Threatening Higher risk than RBCs (room temp storage)
TACO 1 in 200 1 in 100 to 1 in 500 Severe ~300mL per apheresis unit
TRALI 1 in 8,000 1 in 5,000 to 1 in 12,000 Life-Threatening Reduced with male-predominant donors
HLA Refractoriness 10% 5% to 15% (cumulative) Moderate Develops with multiple transfusions

Plasma (FFP) Transfusion Risks

Adverse Event Risk Estimate 95% Credible Interval Severity Key Notes
Allergic (Mild) 1 in 70 1 in 50 to 1 in 100 Mild 100% plasma content
TACO 1 in 200 1 in 100 to 1 in 500 Severe ~250mL per unit
TRALI 1 in 7,000 1 in 5,000 to 1 in 10,000 Life-Threatening Historically highest TRALI risk product
Citrate Toxicity 1 in 100 1 in 50 to 1 in 200 (massive tx) Moderate Risk with rapid/massive transfusion
Anaphylaxis 1 in 30,000 1 in 20,000 to 1 in 50,000 Life-Threatening Consider IgA deficiency

Infectious Disease Transmission Risks

Blood supply safety: Modern blood screening with nucleic acid testing (NAT) has made transfusion-transmitted infections extremely rare.
Sources: REDS-III Program | Busch 2019 | FDA Fatalities
HIV Transmission
Screening: NAT + antibody testing
Window period: ~9 days with NAT
< 1 in 2,300,000
Hepatitis C Transmission
Screening: NAT + antibody testing
Window period: ~3-5 days with NAT
< 1 in 2,000,000
Hepatitis B Transmission
Screening: NAT + HBsAg + anti-HBc
Window period: ~20-22 days with NAT
1 in 300,000 to 1 in 1,000,000
Bacterial Contamination (Symptomatic)
RBC: 1 in 250,000 to 1 in 500,000; Platelets: 1 in 25,000 to 1 in 75,000
Parasitic Infections (Babesia, Malaria, etc.)
1 in 100,000 to 1 in 1,000,000 (varies by region)
Prion Disease (vCJD)
Extremely rare (cases reported in UK)

References & Citations

Evidence Sources: Risk estimates in this tool are derived from published literature, hemovigilance data, and clinical guidelines. Click on links to access source materials.
Hendrickson 2016

Incidence of transfusion reactions: a multicenter study

Hendrickson JE, Roubinian NH, et al.

Transfusion (2016); 56(10): 2587-2596

View Source (DOI)
Delaney 2016

Transfusion reactions: prevention, diagnosis, and treatment

Delaney M, Wendel S, Bercovitz RS, et al.

Lancet (2016); 388(10061): 2825-2836

View Source (DOI)
Tormey 2019

Transfusion-related RBC alloantibodies: induction and consequences

Tormey CA, Hendrickson JE

Blood (2019); 133(17): 1821-1830

View Source (DOI)
Vamvakas 2009

Transfusion-related mortality: the ongoing risks of allogeneic blood transfusion

Vamvakas EC, Blajchman MA

Blood (2009); 113(15): 3406-3417

View Source (DOI)
SHOT UK

Serious Hazards of Transfusion Annual Reports

SHOT UK Haemovigilance Scheme (2020-2023)

Comprehensive UK hemovigilance data on all transfusion adverse events

View Reports
FDA Fatalities

Fatalities Reported to FDA Following Blood Transfusion

U.S. Food and Drug Administration (2019-2023)

Official US transfusion fatality data including AHTR, TRALI, TACO deaths

View Data
AABB Technical Manual

Technical Manual, 21st Edition

AABB (American Association of Blood Banks) (2023)

Authoritative reference for blood banking and transfusion medicine

View Resource
REDS-III

Recipient Epidemiology and Donor Evaluation Study

NHLBI REDS Program (2010-2023)

Large-scale US blood safety surveillance including TTI residual risks

View Program
Educational Use Only

This tool provides evidence-based risk estimates from published literature and hemovigilance data. It is intended to support informed consent discussions and is for educational purposes only.

Important: Actual transfusion risks may vary based on individual patient factors, product modifications, and institutional practices. Always follow your institution's informed consent policies and procedures.