Chinese mainland has a high annual clinical plasma demand gap, and the population blood donation rate is lower than the global average. Stringent restrictions on blood donors may be one of the reasons for this condition.
Written by |Wang Chenguang.
Every winter is the blood shortage season in Chinese mainland, especially in cities like Beijing, where large hospitals are concentrated. Every season, many science enthusiasts familiar to me will meet together to go to blood centers around the world to donate blood on a voluntary basis. But in many cases, people are told they can't donate blood for a variety of reasons, one of the most common reasons being high blood pressure.
The author encountered a similar situation when I went to a blood donation center in a city a few days ago. While registering her personal information, she happened to be begging a middle-aged woman to beg the staff to let her donate blood. From the conversation between them, we have a general understanding of the ins and outs of the matter, the middle-aged woman has someone in her family who is seriously ill and urgently needs blood transfusion, but the hospital is short of blood and cannot provide enough blood in time. In this case, if a family member or friend donates blood, the patient can be given priority to using the same amount of blood.
On one side are middle-aged women who are anxious to donate blood, and on the other are responsible blood center staff. There are two reasons for refusing to donate blood from a middle-aged woman: first, she was found to have high blood pressure at the sceneSecond, ask about the medical history, the patient has the experience of taking antihypertensive drugs. When the middle-aged woman pleaded over and over again, the staff gradually became impatient, took out the blood donation manual, flipped to the section on blood pressure requirements for blood donors, and told the middle-aged woman: It's not that we don't let you donate, the regulations are here, it's all for your safety.
It is understandable that blood donation will have requirements for the physical health of the blood donor, which is not only the protection of the blood donor, but also the protection of the blood recipient. People may not be able to donate blood temporarily or permanently in some cases, including: people with certain infectious diseases or symptoms of illness, such as colds, flu, viral hepatitis, AIDS, etc.;People who have a history of blood transfusion or have injected drugs for a certain period of time;Patients with certain leukemias, malignant tumors;Pregnant or lactating females (donating blood can be an additional burden on the body, and it is generally not recommended to donate blood during pregnancy or breastfeeding);Weight below the prescribed standard (which may make the donor overtired or have other health problems).
But people who don't have high blood pressure and take antihypertensive drugs can't donate blood
Check the regulations of any blood donation collection point in Chinese mainland, the blood pressure requirements for blood donors are systolic blood pressure (high pressure) between 90-140 mmHg (unit), diastolic blood pressure (low pressure) between 60-90, and the difference between systolic and diastolic blood pressure is not less than 30.
However, the World Health Organization has not made specific regulations on blood pressure and other requirements for blood donors, and the United States limits hypertension to systolic blood pressure no higher than 180 and diastolic blood pressure no higher than 100;The lower blood pressure requirements at the time of blood donation are basically the same as those of healthy people, with a systolic blood pressure of at least 90 and a diastolic blood pressure of at least 50.
If a person with high blood pressure is taking antihypertensive drugs to maintain his blood pressure within the normal range, can he donate blood?Chinese mainland's rules are no, while the United States does not have this restriction.
Let's look at the blood pressure regulations for blood donors in other countries and regions. Countries and regions with high enthusiasm for blood donation, such as Europe and Japan, generally do not have strict blood pressure regulations in blood donation restrictions, and hypertensive patients who do not take antihypertensive drugs cannot donate blood. In some Q&A on the relationship between blood pressure and blood donation, you can see a general requirement for blood pressure: systolic blood pressure is usually between 90 and 180;Diastolic blood pressure is required to be between 50 and 100. The other is that blood pressure needs to be relatively stable, not fluctuating or unstable.
So what kind of evidence is behind this regulation in Chinese mainland?If it is for donor protection, if there is a health risk for people with high blood pressure or people taking antihypertensive drugs to control their blood pressure. However Chinese mainland there is no evidence under this provision to support that blood donation by hypertensive patients is not good for health, nor is there any evidence that the blood of hypertensive patients is harmful to the recipient.
Some popular science articles have made some explanations for this national regulation, for example, a respiratory doctor wrote that "hypertensive patients often have hyperlipidemia, atherosclerosis, etc., especially patients with coronary atherosclerosis, if they donate blood, the process of blood donation may induce transient myocardial ischemia, or even acute angina." In addition, due to the short-term decrease in blood volume after blood donation, blood viscosity increases, and thrombosis is easy to occur, which increases the incidence of diseases such as cerebral infarction and deep vein thrombosis." There is no scientific basis for such explanations, especially the fear that "blood donation will increase blood viscosity", which is similar to the fear that every glass of wine poured from a bottle will increase the remaining alcohol in the bottle. In fact, due to the promotion of drinking more water before and after blood donation (it is generally recommended to drink at least 500 ml more than the usual water intake before donating blood), the blood viscosity of blood donors will decrease slightly during the whole process.
Researchers in the UK conducted a meta-analysis aimed at the safety of blood donation in people with high blood pressure or type 2 diabetes. They found no conclusive evidence that baseline hypertension, hypertension**, or diabetes increase the risk of adverse effects after donation.
So, does the blood of people who receive blood from people with high blood pressure or who take antihypertensive drugs have any health effects on the recipient?This worry is also unfounded. These drugs that regulate blood pressure work in transfuses with high blood pressure, but the drug components are not transferred to the recipient's blood at high concentrations during transfusion, and trace amounts of these drugs do not affect the availability or safety of the blood.
The limiting criteria for hypertension in blood donors in Chinese mainland are the same as the diagnostic criteria for clinical hypertension, which are systolic blood pressure higher than 140 and diastolic blood pressure higher than 90;The age limit for blood donation in Chinese mainland is 18-55 years old, so 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 Chinese mainland are: the incidence of hypertension in the 18-24 age group is 4%, and the incidence of hypertension in the 25-34 age group is 61%, 35-44 years old 15%, 45-54 years old 296%。That is, people of each age group who have the corresponding proportion of the above are not eligible to donate blood.
Blood pressure restrictions are just one of the areas where blood donor requirements in Chinese mainland differ from those in other countries.
In terms of age requirements, Chinese mainland stipulates 18-55 years old;For multiple blood donors who have not reacted to blood donation in the past and meet the requirements of health examination, the age can be relaxed to 60 years old. In the United States, you must be at least 17 years old to donate blood on your own, and you can go up to 16 years old with the consent of your parents and guardians. But there is no upper age limit for blood donation, as long as you are in good health.
For non-first-time blood donors, the international maximum age limit for whole blood donors is 65 years old, and the maximum age limit for blood donors is 60 years old. New Zealand's maximum age limit for first-time blood donors is 60 years and 70 years for regular donorsSouth Korea, 64 years old;In Australia, the maximum age limit for first-time blood donors is 60 years, which can be extended to a maximum of 80 years with the approval of a general practitionerHong Kong and Taiwan both have a maximum age limit of 65 for first-time blood donors.
In terms of the frequency of blood donation, for whole blood donation, the Chinese mainland stipulates that the interval between two donations is not less than 6 months, that is, a maximum of two times a year. In the United States, the interval between blood donations is 56 days, and whole blood can be donated up to 6 times a year.
Just by comparing the three requirements of blood pressure, age and blood donation frequency, it is easy to understand that the restrictions on blood donors in Chinese mainland are much harsher than those in developed countries, and many people lose the opportunity to donate blood.
Nearly 1200 million blood donations, of which 40% were contributed by developed countries, which account for 16% of the world's population. In Chinese mainland, which accounts for 18% of the population, the total number of blood donations in 2022 will be 16 million, accounting for about 13% of the global blood donation. The United States, with a population of only 1 4 in Chinese mainland, donated 13.6 million blood last year, and the blood donation rate of the American population is about three times that of China.
According to reports, the annual clinical plasma demand gap in Chinese mainland is as high as 5,000 tons. It's time to change the rules on blood donation, remove those unreasonable restrictions, and get more people to join the ranks of giving.
References. 1]
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 Ph.D. in biology, a former researcher at the Sidney Kimmel Cancer Center at Thomas Jefferson University, an associate professor in the Department of Cancer Biology, a researcher at the Institute of Radiation Medicine of the Chinese Academy of Medical Sciences, the director of the Radiation Injury Protection and Drug Research Office, and a professor and doctoral supervisor at Peking Union Medical College.
This article is supported by the Science Popularization China Star Program Project, produced by the Science Popularization Department of the China Association for Science and Technology, supervised by the China Science and Technology Press, Beijing Zhongke Galaxy Culture Media***