It's blood shortage season again, but these blood donors are rejected

The annual clinical plasma demand gap in mainland China is high, while the blood donation rate of the population is lower than the global average. The strict restrictions on blood donors may be one of the reasons for this situation.

Written by | Wang Chenguang

Every winter is a blood shortage season in mainland China, especially in cities like Beijing where large hospitals are concentrated. During this season, many science enthusiasts I know will go to blood centers around the country to donate blood on a voluntary basis. But in many cases, people are told they cannot donate blood for various reasons, one of the most common reasons being high blood pressure.

I encountered a similar situation when I went to a blood donation center in a certain city a few days ago. When registering my personal information, I happened to meet a middle-aged woman who was begging the staff to let her donate blood. From their conversation, I roughly understood the whole story. Someone in the middle-aged woman's family was seriously ill and urgently needed a blood transfusion, but the hospital was short of blood and could not provide enough blood in time. In this case, if relatives and friends go to donate blood, the patient can be given priority to use the same amount of blood.

On one side was a middle-aged woman who was anxious to donate blood, and on the other side was a responsible blood center staff. There were two reasons for refusing the middle-aged woman's blood donation: first, she was found to have high blood pressure on the spot; second, after asking about her medical history, the patient had taken antihypertensive drugs. As the middle-aged woman begged again and again, the staff gradually became impatient, took out the blood donation manual, turned to the part about the blood pressure requirements for blood donors, and told the middle-aged woman: It's not that we don't want you to donate, the rules are here, all for your safety.

Understandably, blood donation requires the donor to be in good health, which is a protection for both the donor and the recipient. In some cases, people may be temporarily or permanently unable to donate blood, including: those with certain infectious diseases or symptoms of diseases, such as colds, flu, viral hepatitis, AIDS, etc.; those who have a history of blood transfusion or have injected drugs within a certain period of time; certain leukemia and malignant tumor patients; pregnant or breastfeeding women (blood donation will put an extra burden on the body, and it is generally not recommended to donate blood during pregnancy or breastfeeding); weight below the prescribed standard (may cause excessive fatigue or other health problems for the donor).

But does that mean that patients with high blood pressure or those taking antihypertensive medication are also prohibited from donating blood?

Checking the regulations of any blood donation and collection point in mainland China, the blood pressure requirements for blood donors are that the systolic pressure (high pressure) needs to be between 90-140 mmHg (same unit below), the diastolic pressure (low pressure) is between 60-90, and the difference between systolic and diastolic pressure is not less than 30.

However, the World Health Organization has not made specific regulations on blood pressure requirements for blood donors. The U.S. limit for high blood pressure is that systolic blood pressure cannot be higher than 180, and diastolic blood pressure cannot be higher than 100; the lower limit of blood pressure requirements when donating blood is basically the same as that of healthy people, with systolic blood pressure of at least 90 and diastolic blood pressure of at least 50.

If a patient with high blood pressure relies on antihypertensive drugs to maintain blood pressure within the normal range, can he donate blood? The regulations in mainland China are not allowed, but there is no such restriction in the United States.

Let's look at the regulations on blood pressure of blood donors in other countries and regions. In countries and regions such as Europe and Japan, where people are more enthusiastic about donating blood, there are generally no strict regulations on blood pressure in the blood donation restrictions, and there is a requirement that hypertensive patients who are not taking antihypertensive drugs cannot donate blood. In some questions and answers about the relationship between blood pressure and blood donation, we can see the general requirements for blood pressure: systolic blood pressure is usually required to be 90-180; diastolic blood pressure is required to be 50-100. In addition, blood pressure needs to be relatively stable, not in a fluctuating or unstable state.

So what kind of evidence is behind this regulation in mainland China? If it is for the protection of donors, the premise is that there are health risks for patients with hypertension or patients who take antihypertensive drugs to control their blood pressure to donate blood. However, this regulation in mainland China does not provide evidence to support that blood donation by patients with hypertension is detrimental to health, nor does it provide evidence that the blood of patients with hypertension is harmful to blood recipients.

Some popular science articles have explained this national regulation. For example, a respiratory doctor wrote that "patients with hypertension often have complications such as high blood lipids and atherosclerosis, especially those with coronary atherosclerosis. If they donate blood, the process of blood donation may induce transient myocardial ischemia or even acute angina pectoris. In addition, due to the short-term decrease in blood volume and increase in blood viscosity after blood donation, blood clots are more likely to occur, increasing the incidence of diseases such as cerebral infarction and deep vein thrombosis." This kind of explanation lacks scientific basis, especially the worry that "blood donation leads to increased blood viscosity", which is similar to the worry that every time a glass of wine is poured out, the alcohol content of the remaining wine in the bottle will increase. In fact, because it is recommended to drink more water before and after blood donation (it is generally recommended to drink at least 500 ml more water before donating blood), the blood viscosity of the donor will decrease slightly during the whole process.

British researchers conducted a meta-analysis to investigate the safety of blood donation in patients with hypertension or type 2 diabetes. They found no conclusive evidence that baseline hypertension, hypertension treatment, or diabetes increased the risk of adverse reactions after blood donation.

So, will receiving blood from a patient with hypertension or a blood donor who is taking blood pressure medication affect the health of the recipient? This worry is unnecessary. These blood pressure regulating drugs work in the body of the recipient with hypertension, but the drug components will not be transferred to the recipient's blood in high concentrations during blood transfusion. Trace amounts of these drugs do not affect the availability or safety of the blood.

The restriction standard for blood donors with high blood pressure in mainland China is the same as the diagnostic standard for clinical hypertension, which is systolic blood pressure higher than 140 and diastolic blood pressure higher than 90. The age range for blood donation stipulated in mainland China is 18-55 years old. Based on this, we can roughly estimate how many people in China cannot donate blood because of this regulation. The epidemiological data of hypertension in different age groups in mainland China are: the incidence of hypertension in the 18-24 age group is 4%, 6.1% between 25-34 years old, 15% between 35-44 years old, and 29.6% between 45-54 years old. In other words, there are people in each age group with the above corresponding proportion who are not eligible to donate blood.

Blood pressure limits are just one of the ways in which mainland China's requirements for blood donors differ from those in other countries.

In terms of age requirements, mainland China stipulates that the age limit is 18-55 years old; for multiple blood donors who have no previous blood donation reactions and meet the health examination requirements and voluntarily request to donate blood again, the age limit can be extended to 60 years old. The United States stipulates that one must be at least 17 years old to donate blood on their own, and it can be advanced to 16 years old with the consent of parents/guardians. However, there is no upper age limit for blood donation, as long as you are healthy.

For non-first-time blood donors, the upper age limit for whole blood donors is mostly 65 years old, and the upper age limit for blood component donors is mostly 60 years old. New Zealand has an upper age limit of 60 years old for first-time blood donors and 70 years old for regular blood donors; South Korea has an upper age limit of 64 years old; Australia stipulates that the upper age limit for first-time blood donors is 60 years old, which can be extended to 80 years old with the approval of a general practitioner; Hong Kong, China and Taiwan have an upper age limit of 65 years old for first-time blood donors.

In terms of blood donation frequency, the Chinese mainland stipulates that the interval between two whole blood donations should be no less than 6 months, which means a maximum of two donations per year. The United States stipulates that the interval between two blood donations should be 56 days, and a maximum of six whole blood donations per year.

Just by comparing the three requirements of blood pressure, age and frequency of blood donation, it is easy to understand that the restrictions on blood donors in mainland China are much more stringent than those in developed countries, and many people have lost the opportunity to donate blood as a result.

Nearly 120 million blood donations were collected worldwide last year, of which 40% were contributed by developed countries, which account for 16% of the world's population. In mainland China, which accounts for 18% of the population, the total blood donations in 2022 were 16 million, accounting for about 13% of the global blood donations. The United States, which has a population only one-fourth of that of mainland China, donated 13.6 million blood last year, and the blood donation rate of the American population is about three times that of China.

It is reported that the annual clinical plasma demand gap in mainland China is as high as 5,000 tons. It is time to change the blood donation regulations, cancel those unreasonable restrictions, and allow more people to join the ranks of donating love.

References

[1] http://www.nhc.gov.cn/yzygj/wcjkzs/201901/1eabccf202ff4767a52f0fd5a774cd8f.shtml

[2] https://www.redcrossblood.org/donate-blood/how-to-donate/eligibility-requirements.html

[3] Stainsby D, Brunskill S, Chapman CE, Dorée C, Stanworth S. Safety of blood donation from individuals with treated hypertension or non-insulin dependent type 2 diabetes - a systematic review. Vox Sang. 2010 Apr;98(3 Pt 2):431-40.

The author of this article is a PhD in biology. He has served as a researcher at the Sidney Kimmel Cancer Center of Thomas Jefferson University, an associate professor in the Department of Cancer Biology, a researcher/director of the Radiation Damage Protection and Drug Research Laboratory at the Institute of Radiation Medicine, Chinese Academy of Medical Sciences, and a professor/doctoral supervisor at Peking Union Medical College. He is currently engaged in the research and development of anti-tumor drugs.

This article is supported by the Science Popularization China Starry Sky Project

Produced by: China Association for Science and Technology Department of Science Popularization

Producer: China Science and Technology Press Co., Ltd., Beijing Zhongke Xinghe Culture Media Co., Ltd.

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