Donor blood: components and transfusion rules

Donated blood and its components are needed for injuries, surgeries, blood cancers, anemia, obstetric hemorrhages, and congenital and acquired coagulopathies. Safety begins with proper donor selection and processing of blood into components: red blood cells, plasma, and platelets. This approach makes it possible to treat dozens of different conditions and use each donor visit economically. [1]

The World Health Organization recommends building blood services around voluntary, unpaid donors, as this improves supply sustainability and safety. Priority is given to quality, traceability, and national coordination to ensure timely and sufficient availability of blood and blood components. [2]

Each donation is accompanied by mandatory laboratory tests to detect infections, group typing, and compatibility testing. These are mandatory components of a unified quality system, without which the component is not approved for transfusion to a patient. [3]

In 2024, a new regulation on quality and safety standards for substances of human origin was approved in Europe. It harmonizes requirements for the donation of blood and other substances, creates a coordinating council, and introduces uniform approaches to risks. Implementation will be phased in over the coming years. [4]

Who can be a donor: basic criteria and updated questionnaires

Before donation, a questionnaire and medical examination are conducted. In many countries, the minimum hemoglobin thresholds are at least 12.0 grams per deciliter for women and at least 13.0 grams per deciliter for men. This reduces the risk of symptomatic anemia in the donor and helps maintain the quality of the components. [5]

In Europe, thresholds of 125 grams per liter for women and 135 grams per liter for men are widely used. At the same time, the practice of monitoring iron stores with ferritin assessment is growing, allowing for flexible management of donation frequency and the prevention of iron deficiency in regular donors. [6]

Since 2023, a number of countries have introduced individualized risk questionnaires to assess the likelihood of transmission of the human immunodeficiency virus and other infections. This approach replaces outdated categorical exclusions and is based on the specific behavior and risk factors of each individual. [7]

In the United States of America, updated guidelines for individually tailored questions in donor questionnaires were published in 2025. They standardize approaches to eligibility and clarify criteria for temporary and permanent exemptions from an infection control perspective. [8]

Table 1. Minimum eligibility criteria for whole blood donation

Criterion	Landmark
Age	According to national regulations, usually from 18 years old
Body weight	Typically 50 kg and above
Hemoglobin in women	Not less than 12.0 grams per deciliter or 125 grams per liter
Hemoglobin in men	Not less than 13.0 grams per deciliter or 135 grams per liter
Inspection and questionnaire	Individual risk assessment and medical monitoring

Basis: World Health Organization recommendations and European practice of hemoglobin thresholds. [9]

Types of donation: what exactly does a donor donate and how often can it be done?

Whole blood is the most common type of donation. Blood is separated into its components, and the standard donation volume is approximately 450 milliliters. Most systems allow whole blood donations no more than once every 8 weeks to allow the body to replenish red blood cells and iron stores. [10]

Platelet apheresis allows for the targeted collection of platelets. The procedure takes longer, but the donor loses fewer red blood cells. Under typical protocols, platelets can be donated significantly more frequently than whole blood, provided the intervals and safety indicators are met. [11]

Plasma apheresis is used to obtain large volumes of plasma with minimal loss of red blood cells. This type of donation is used for both clinical transfusions and further fractionation into medicinal products, but its own intervals and requirements apply. [12]

Many services also use double red blood cell donations via apheresis. The interval between these donations is usually longer than after standard whole blood donations because iron loss is greater and it takes longer to replace it. [13]

Table 2. Main types of donation and guidelines

View	What do they get?	Typical volume	Frequency guidelines
Whole blood	Red blood cells, plasma, platelets after separation	About 450 ml	About once every 8 weeks
Platelet apheresis	Platelet concentrate	Individually	Frequent donations are possible while monitoring the indicators.
Plasma apheresis	Plasma	Individually	More often than whole blood, subject to standards
Double dose of red blood cells	Red blood cells	More than with whole blood	The interval is longer due to iron loss

Basis: reference materials of blood services and circulars on components. [14]

What happens on donor day: preparation, procedure, and recovery

Preparation includes drinking plenty of fluids, eating light, salty foods, and avoiding alcohol and strenuous exercise the day before. At the collection point, a questionnaire is administered, and hemoglobin, pulse, blood pressure, and temperature are measured. If any discrepancies are detected, the donor is temporarily or permanently excluded for their own safety. [15]

During the procedure, donors' well-being is monitored. The most common acute reactions in donors are vasovagal episodes with dizziness and brief syncope, as well as local hematomas. The incidence of such events is low and is reduced with proper preparation and monitoring. [16]

Following donation, rest, additional fluid intake, careful removal of the dressing, and avoidance of strenuous physical activity on the day of the procedure are recommended. Organized donor well-being and vasovagal reaction prevention programs further reduce the risk and increase the likelihood of repeat donations. [17]

During follow-up visits, the blood service monitors blood counts and provides personalized recommendations on intervals, nutrition, and iron supplementation based on gender, donation frequency, and laboratory data. This targeted prevention makes donation safer for donors. [18]

Table 3. Common reactions in donors and how to prevent them

Reaction	What is this	Prevention
Vasovagal	Dizziness, sweating, short-term fainting	Hydration, salty snacks, trained staff, post-procedure monitoring
Local hematoma	Pain and bruising at the venipuncture site	Correct fixation of the bandage, rest of the limb
Rare: paresthesia, nerve pain	Nerve irritation during puncture	Venipuncture technique and changing the collection site
Delayed complaints, fatigue	More often after frequent donations	Individual intervals, prevention of iron deficiency

Basis: Hemovigillance reports and clinical guidelines on donor welfare. [19]

Laboratory safety: what tests are all donations subject to?

The World Health Organization recommends mandatory testing of every donation for human immunodeficiency virus, hepatitis B virus, hepatitis C virus, and syphilis. Blood group testing for A, B, O, and Rh-D is also performed to ensure compatibility. This is the minimum global standard. [20]

In countries with extensive programs, nucleic acid amplification is used to detect pathogen DNA or RNA, which reduces the "gray window" between infection and detection. The list of mandatory or recommended tests may include certain region-specific infections, such as West Nile virus or babesiosis. [21]

In 2025, regulators clarified recommendations for hepatitis B surface antigen testing and combinations of methods. The documents discuss the role of nucleic acid amplification for hepatitis B virus and antibodies to the core antigen in adequately reducing the risk of transmission. This reflects a shift toward more sensitive algorithms. [22]

The Centers for Disease Control and Prevention (CDC) reminds that bacterial contamination remains a key infectious risk for platelets, as they are stored at room temperature. Therefore, many facilities are using bacterial control strategies and new platelet processing technologies. [23]

Table 4. Basic panel screening of donations

Category	Examples of tests
Human immunodeficiency virus	Combined antigen and antibody tests, nucleic acid amplification
Hepatitis B virus	Surface antigen, antibodies to core antigen, nucleic acid amplification
Hepatitis C virus	Antibodies, nucleic acid amplification
Syphilis	Serological screening tests
Regional risks	West Nile virus, babesiosis according to regional requirements

Basis: World Health Organization, regulatory lists and circulars of blood services. [24]

Donation Intervals, Iron, and Ferritin: How to Protect the Donor

A single donation of whole blood results in a loss of approximately 220-250 milligrams of iron. Frequent donations increase the risk of iron deficiency and delayed symptoms, especially in young donors and women. Therefore, blood services limit frequency and gradually introduce ferritin monitoring. [25]

Many countries adhere to a minimum interval of 56 days for whole blood. Several European guidelines differentiate between genders, as well as a maximum number of donations per year. Data from large studies show that more frequent donations increases donation volumes, but increases the incidence of low hemoglobin and depleted iron stores. [26]

A ferritin-guided approach with individualized intervals improves hemoglobin and ferritin levels and reduces the incidence of iron deficiency in donors. Randomized and quasi-experimental studies in Europe confirm the benefits of such strategies, particularly in frequent donors. [27]

In addition to intervals, a short course of iron supplements after donation is widely discussed. Some guidelines advocate low doses of elemental iron for several weeks as a way to speed up replenishment of stores, especially with frequent donations. The decision is made individually, taking into account tolerance and laboratory data. [28]

Table 5. Guidelines for donation frequency and iron protection

Parameter	Landmark
Whole blood interval	Approximately 56 days, in some countries it is longer for women
Iron loss per donation	About 220-250 milligrams
Ferritin control	Recommended for frequent donors, reduces the risk of deficiency
Iron supplements	Short course according to individual indications

Basis: data from research and practice of blood services. [29]

Temporary and permanent deferrals: travel, infections, procedures

After traveling to malaria-endemic areas, most donors receive a temporary exemption. In 2024, the Centers for Disease Control and Prevention confirmed a shortening of the standard exemption period for travelers to three months, although longer periods apply for former residents and malaria survivors. Discussion is underway to replace longer exemptions with selective testing. [30]

During the warm season, Europe monitors West Nile virus activity. Blood services implement temporary diversions or testing for donors from affected areas to reduce the risk of transmission. Regional approaches are updated annually based on the epidemiological situation. [31]

Donor questionnaires include questions about recent procedures, dental work, tattoos, piercings, vaccinations, antibiotic use, and acute infections. In most cases, this results in a short deferral until full recovery or after a specified period. [32]

The introduction of individually targeted questions instead of general category restrictions helps maintain safety while reducing discriminatory practices. This is reflected in guidelines and official updates in recent years. [33]

Table 6. Frequent reasons for temporary removal and typical time limits

Situation	Standard term
Traveling to a malaria-ridden area	About 3 months for travelers, longer for former residents and those who have had malaria
West Nile virus in the region	Seasonal measures: diversion or testing according to local rules
Acute infections, fever	Until complete recovery and normalization of test results
Recent tattoos, piercings	Several months depending on the conditions of the procedure
Recent major dental intervention	Up to 1 month according to regional regulations

Basis: regulatory and expert sources. [34]

What happens to the components: storage, shelf life and purpose

Red blood cell-containing components are stored at approximately 1 to 6 degrees Celsius, with a shelf life typically of up to 42 days, depending on the additive solution. This ensures the preservation of oxygen transport function, but requires an uninterrupted "cold chain." [35]

Platelets are stored at approximately 20-24 degrees Celsius with constant gentle agitation, for a maximum of 7 days in most systems, using bacterial risk control strategies. This regimen maintains viability but requires strict microbiological safety measures. [36]

Frozen plasma is stored at temperatures of minus 18 degrees Celsius or lower for up to 1 year; after thawing, it is stored for a limited time at temperatures between 1 and 6 degrees Celsius, depending on the plasma type. Regulations specify the conditions for different types of plasma. [37]

Maintaining temperature control at all stages, from collection point to delivery, is critical to efficiency and safety. The World Health Organization emphasizes the importance of a well-established cold chain with quality control and traceability. [38]

Table 7. Storage and shelf life of the main components

Component	Storage temperature	Typical term
Red blood cells	From 1 to 6 °C	Up to 42 days
Platelets	Around 20-24°C with gentle stirring	Up to 7 days with bacteria control strategy
Frozen plasma	Not higher than minus 18 °C	Up to 1 year
Plasma after defrosting	From 1 to 6 °C	Limited, depending on the type of plasma and regulations

Basis: Circulars on the use of components and materials of blood services. [39]

Risks to the recipient and why strict safety is important

Even with a modern quality system, transfusions can be associated with complications for the recipient. Common complications include volume overload with pulmonary edema, which manifests as shortness of breath and radiographic signs of edema within a few hours after transfusion. Correct indications, volume selection, and transfusion rate are important for prevention. [40]

Platelet transfusions carry a risk of bacterial contamination due to storage at room temperature, so bacterial testing and processing technologies are used. These measures significantly reduce the risk, but do not completely eliminate it, justifying cautious administration of components. [41]

Another serious but rare complication is transfusion-associated acute lung injury. Preventive measures include rational selection of components, limiting unnecessary transfusions, and adhering to indications. All these practices are supported by standards and ongoing analysis of adverse events. [42]

Thus, rigorous donor selection, advanced laboratory algorithms, and appropriate clinical management minimize risks and ensure patients receive maximum benefit from each transfusion. This justifies high demands on quality and discipline at all stages. [43]

Table 8. Recipient safety: what reduces the risk of complications

Risk	What reduces the risk
Volume overload	Evaluation of indications, minimum sufficient doses, rate control
Bacterial risk of platelets	Testing, processing technologies, shelf life limitations
Immune reactions	Correct typing and selection, minimization of unnecessary transfusions
Infectious risks	Panel screening of each donation using modern algorithms

Basis: transfusion safety guidelines and adverse reaction reports. [44]

Briefly about the main thing

Donation saves lives, and modern blood services are built on individual risk assessments, mandatory laboratory screening of each donation, proper management of donor iron levels and reserves, and strict adherence to temperature regulations for component storage. This comprehensive set of measures makes donor blood an effective and safe therapeutic resource. [45]