By He Zi
A local report from Dezhou Evening News in China’s eastern Shandong province has drawn widespread attention after a blood center identified an exceptionally rare blood type while screening nearly 20,000 donors.
The case involves the Jk(a-b-) blood type, informally referred to online as “diamond blood,” a classification far rarer than the better-known Rh-negative blood, often nicknamed “panda blood” in China.
While the discovery highlighted the diversity and complexity of human blood group systems, it also triggered a wave of unease, suspicion, and dark humor across Chinese social media platforms.
A rare medical finding, and an uneasy public reaction
Medical estimates suggest that the Jk(a-b-) blood type occurs in roughly one out of every 10,000 to several tens of thousands of people, depending on population group.
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Online reactions, however, quickly drifted away from medical curiosity. Some users half-jokingly warned that the individual could one day be declared “brain-dead,” urging him to open a Douyin account and post daily videos as proof of safety. Others framed the discovery as a symbol of vulnerability rather than rarity.
At the center of the discussion lies a basic question: what exactly is this blood type, and why does it provoke such anxiety?
Blood type compatibility is never absolute
Medical professionals caution that claims suggesting “diamond blood” can be transfused into anyone are misleading. Transfusion compatibility always depends on the ABO blood group system.
Only individuals with O-type Jk(a-b-) blood would have relatively broader compatibility, and even then, it does not constitute true universality. In clinical practice, the term “universal donor” typically refers to O-type Rh-negative (O−) blood, which lacks the major A, B, and D antigens.
Beyond ABO and Rh: how blood types are classified
Most people are familiar with the ABO system, which classifies blood into A, B, AB, or O types. In fact, scientists have identified more than 40 blood group systems, including Rh, Kidd, and Diego.
Each system is defined by specific antigens on the surface of red blood cells, functioning much like biological identification markers. When incompatible blood is transfused, the recipient’s immune system may attack the foreign cells, leading to hemolytic reactions that can be severe or fatal.
‘Panda blood:’ rare, but manageable
Among China’s Han population, approximately 0.3 percent are Rh-negative, earning it the nickname “panda blood.” By contrast, around 15 percent of people of European descent are Rh-negative.
Individuals with this blood type must receive compatible blood during transfusions. Pregnant women may face additional risks related to hemolytic disease of the newborn. Today, however, blood banks maintain specialized registries, and clinical management is generally reliable.
The Bombay blood type: rarer still
Another extreme example is the Bombay blood type, sometimes nicknamed “dinosaur blood.” This type results from the absence of the H antigen, making it incompatible even with O-type blood.
The incidence is roughly one in 10,000 in India and significantly lower in China, where only a small number of cases have been documented. In December 2025, one such case was identified in Guangxi, drawing attention within the medical community.
What makes ‘diamond blood’ different
The Jk(a-b-) blood type identified in Dezhou belongs to the Kidd blood group system, the 18th blood group system discovered in humans.
Most people carry either the Jkᵃ or Jkᵇ antigen on their red blood cells. Individuals with Jk(a-b-) lack both antigens entirely, including the associated Jk3 antigen, due to a genetic mutation.
As a result, the blood type is exceptionally rare. Among Asian populations, incidence estimates fall below one in 10,000. Among Caucasians, the rate is approximately 0.14 percent, and among African Americans about 0.05 percent.
The term “diamond blood” reflects its perceived scarcity and value. In daily life, individuals with this blood type face no health differences and require no special care. During transfusions, however, they can receive blood only from donors with the same type.
Incompatible transfusions may trigger delayed hemolytic reactions, in which the immune system attacks transfused red blood cells days or weeks later. Severe cases can lead to kidney failure or death.
Pregnancy also requires special monitoring. If a fetus inherits blood antigens from the father that the mother lacks, blood group incompatibility may occur. For this reason, once such a blood type is identified, blood centers typically establish permanent records and prepare for nationwide coordination in emergencies.
Rare blood types and global preparedness
Other rare blood types include Rh-null, sometimes called “golden blood,” in which all Rh antigens are absent. Fewer than 50 cases have been documented worldwide. Diego-negative blood, another rare type, appears more frequently among Indigenous populations in South America.
Most rare blood types arise from genetic mutations and may cluster within families. Scientists estimate that fewer than 0.1 percent of the global population has a rare blood type.
For transfusion medicine, however, these individuals are critically important. International rare blood banks, including those in the United Kingdom, maintain frozen reserves of rare red blood cells for emergency use.
Why the jokes sound darker than humor
The online discourse surrounding “diamond blood” has been filled with dark humor and suspicion. One widely shared comment read: “Diamond blood? That’s not blood, that’s a mobile jewelry store. If a transfusion is needed, nationwide coordination would cost more than buying a diamond ring.”
Behind the jokes lies a deeper unease. Many netizens instinctively equate “rare” with “high risk,” viewing rare blood types as valuable commodities rather than medical classifications.
Some express fears that individuals with such blood could become targets of medical corruption, organ harvesting, or covert experimentation.
This wave of anxiety, expressed through humor and speculation, reflects not fear of the blood type itself, but a lingering crisis of trust in the healthcare system among parts of the public.
