Transfusion medicine

Blood donation

Donor reactions

Editorial Board Member: Kyle Annen, D.O.
Deputy Editor-in-Chief: Patricia Tsang, M.D., M.B.A.
Evelyn M. Potochny, D.O.

Last author update: 19 July 2021
Last staff update: 19 July 2021

Copyright: 2021,, Inc.

PubMed Search: Blood donor reactions[TIAB]

Evelyn M. Potochny, D.O.
Page views in 2022: 560
Page views in 2023 to date: 812
Cite this page: Potochny EM. Donor reactions. website. Accessed September 26th, 2023.
Definition / general
  • Adverse events related to whole blood or apheresis donation
Essential features
  • Complications may be localized due to phlebotomy or systemic
  • Apheresis donations carry additional risk of hypocalcemia
  • Donor reactions
  • Donor adverse events
  • Donor adverse reactions
  • Donor safety
  • Donor hemovigilance
Clinical features
  • Systemic / syncopal type:
    • Presyncopal, prefaint
    • Loss of consciousness
    • Additional bodily injury from syncope related fall
      • Lacerations, abrasions, head injury, fracture
    • Most often vasovagal
    • May be caused by hypovolemia
      • Decrease in blood pressure with increased pulse rate
  • Phlebotomy related:
    • Hematoma
      • Bruising
    • Arterial puncture
      • Suspect if rapidly pulsating needle, bright red blood
    • Infection
      • Warmth, pain, erythema near phlebotomy site
    • Thrombophlebitis
      • Redness, swelling tracks along vein
    • Upper extremity deep vein thrombosis
      • Very rare; swelling, warmth, pain, possible palpable cord
    • Nerve injury
      • Radiating pain down arm, paresthesia
    • Arm pain
    • Arteriovenous fistula
      • Pulsating mass, bruit on auscultation
  • Systemic other:
    • Citrate toxicity (apheresis collections) causing hypocalcemia from anticoagulant binding calcium
      • Perioral tingling, distal extremity paresthesia
    • Allergic
      • Localized urticaria to rare, severe anaphylactic
    • Other
      • Anxiousness, hyperventilation, headache
  • No universally accepted severity grading system at this time, although proposal in development (Transfusion 2020;60:1231)
  • References: Transfusion 2008;48:1809, Blood Rev 2012;26:33, ISBT: Standard for Surveillance of Complications Related to Blood Donation [Accessed 7 May 2021]
Blood donor screening
  • Blood donors are not screened specifically for risk factors for donor reactions
  • Must be 16 or 17 years old, as determined by state regulations in the U.S.
  • Maximum donation frequency, e.g. every 56 days for whole blood
  • Provided information on donation process, infectious disease testing, potential reactions
  • Screened for overall blood safety using the Donor History Questionnaire (DHQ) as published by the AABB and accepted by the FDA:
    • General state of health
    • High risk behavior for infectious disease
    • Needle sticks / recent tattoos
    • Travel history
    • Medical conditions
    • Recent vaccinations
    • Medications
  • Donors are also screened by a mini physical exam:
    • Point of care hemoglobin
    • Blood pressure
    • Pulse
    • Temperature
    • Skin integrity around anticipated phlebotomy site (typically antecubital fossa)
  • Interview with screener for clarification of any "yes" responses or concerns
  • Reference: Fung: Technical Manual, 19th Edition, 2017
Case reports
  • Presyncopal / syncopal events are generally managed by:
    • Placing individual in supine position with feet elevated (Trendelenburg position), if possible or having seated patient cross and flex legs (Prehosp Emerg Care 2020;24:64)
    • Mitigation strategies include ingesting water or hypertonic fluids to increase predonation blood pressure (Transfusion 2011;51:2727)
    • > 6 hours sleep predonation and increasing muscle tension near the end of the donation have also been associated with fewer vasovagal reactions (Transfus Med Hemother 2014;41:284)
  • If hypovolemic, oral fluids may be encouraged once the patient is stable
  • Allergic reactions typically treated with antihistamines if mild; potentially epinephrine if severe (Am Fam Physician 2017;95:717)
  • Phlebotomy related events are typically managed with pressure, compression, elevation of the arm or ice
    • Hematoma is fairly common in both whole blood and apheresis donors
    • Nerve injury rarely leads to long term sequelae but occasionally requires recovery times of several months
      • In one study, 30% of donors with nerve injury required at least a month for symptom resolution
      • Such extenuating cases may require physician consultation (Transfusion 1996;36:213)
  • Citrate toxicity or hypocalcemia is usually addressed with oral calcium (Popovsky: Transfusion Reactions, 4th Edition, 2012)
  • More severe reactions may be evaluated by the medical director if on site, urgent care or emergency medical system
Board review style question #1
A 22 year old female whole blood donor complained of lightheadedness at the end of her donation, while still recumbent in the collection chair. Her 510 mL blood collection took approximately 11 minutes. Her predonation blood pressure was 116/74 and pulse was 74. Following the incident, her blood pressure was found to be 80/50 and her pulse was 85. Which of the following is the most likely donor reaction and recommended treatment?

  1. Allergic reaction, antihistamines
  2. Arterial puncture, direct pressure over the phlebotomy site
  3. Citrate toxicity, oral calcium carbonate
  4. Vasovagal reaction, Trendelenburg positioning
Board review style answer #1
D. Vasovagal reaction, Trendelenburg positioning. This is consistent with a mild vasovagal reaction and often responds to repositioning the patient with feet above the level of the heart. Alternatively, bearing down to increase muscle tension to increase blood return to the heart may also help, especially if the patient is sitting upright in a chair that does not recline. Allergic reactions (answer A) would most often manifest with pruritus / itching or hives. An arterial puncture (answer B) would cause the needle to rapidly pulsate with bright red blood during collection and the collection bag would fill within a few minutes. Hypocalcemia from citrate toxicity (answer C) occurs during automated collections (such as apheresis component collections or apheresis source plasma collections) and will usually respond to oral calcium supplementation.

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Reference: Donor reactions
Board review style question #2
During a plateletpheresis collection, a 30 year old man complains of numbness and tingling around his mouth and cramping of his muscles in his hands and feet. He has no significant change in vital signs predonation versus immediately after symptom onset. What is the most likely explanation for this type of donor reaction?

  1. Hyperventilation leading to lowered bicarbonate levels
  2. Hypocalcemia from citrate anticoagulant binding calcium
  3. Hypovolemia from dehydration
  4. Sensory nerve injury from phlebotomy
Board review style answer #2
B. Hypocalcemia from citrate anticoagulant binding calcium. The symptoms are most compatible with citrate toxicity. The anticoagulant necessary to prevent extracorporeal blood clotting in the apheresis tubing binds calcium, leading to these symptoms of hypocalcemia. Hyperventilation (answer A) may also cause numbness and tingling in the extremities. However, citrate toxicity is more common during an automated apheresis collection. Hypovolemia (answer C) would most likely lead to the sensation of lightheadedness and a decrease in blood pressure with increase in heart rate. Nerve injury (answer D) would cause paresthesia in the ipsilateral arm where phlebotomy was performed.

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