Do you know who can donate blood to you or who can you donate blood to? Blood donation may not be complex, but it does need to be compatible with yours and vice-versa. The blood types are determined by the presence or absence of certain antigens - substance that can trigger immune response if they are foreign to the body.

There are four major blood groups which are determined by the presence or absence of two antigens, A and B, on the surface of red blood cells. There is also a protein called the Rh factor, which can either be present (+) or absent (-), which creates A+, A-, B+, B-, O+. O-, AB+, AB- blood types.

Group A blood type has only A antigens on red blood cells and B antibody in the plasma. B has only B antigen on red cells and A antibody in the plasma. AB has both A and antigens on red cells, but neither A nor B antibody is present in the plasma. O has neither A nor B antigens on red cells, but both A and B antibody are present in the plasma.

Blood Type And Who Can You Donate To?

Your blood type determines who can you donate to. This is because there are very specific ways in which blood types must be matched for safe transfusion. The right blood transfusion could actually save you, while the wrong one could be lethal. Also, Rh-negative blood is given to Rh-negative patients and Rh-positive or Rh-negative blood can only be given to Rh-positive patients.

If you are O blood type, you can donate to O, A, B, and AB, if you are A blood type, you can donate to A and AB, if you are B blood type, you can donate to B and AB, however if you are AB, you can only donate to AB.

Who Can You Receive Blood From?

If you are O blood type, you can only receive from O. If you are A, you can receive from type A and O. If you are blood type B, you can receive from type B and O. If you are AB, you are lucky, you can receive blood from O, A, B, and AB.

There are more than 600 other known antigens, the presence or absence of which creates "rare blood types". Certain types are unique to specific ethnic or racial groups, this is why an African-American blood donation can be the best hope for the needs of patients with sickle cell disease, as per the Red Cross Organization.

Universal Blood Donor

Type O is one in high demand, as it can donate blood to anyone. O negative blood type is the universal blood type, which can donate to everyone, especially during the emergency transfusions and for immune deficient infants.

Who Have These Blood Types In US?

In the US, 37% Caucasian, 47% African-American, 39% Asians, and 53% Latino-American are O-positive. However, only 8% of Caucasian, 4% of African-American, 1% Asian, and 4% Latino=Americans are O-negative.

A+: 33% Caucasian, 34% African-American, 27% Asian, 29% Latino-American

A-: 7% Caucasian, 2% African-American, .5% Asian, 2% Latino-American

B+: 9% Caucasian, 18% African-American, 25% Asian, 9% Latino-American

B-: 2% Caucasian, 2% African-American, .4% Asian, 1% Latino-American

AB+:3% Caucasian, 4% African-American, 7% Asian, 2% Latino-American

AB-: 1% Caucasian, .3% African-American, .1% Asian, .2% Latino-American

A team of researchers at the All India Institute of Medical Sciences (AIIMS) in Patna has made a significant breakthrough in understanding the link between heatstroke and fatalities.

The study published in the Medico-Legal Journal identified a specific brain center and vascular injury patterns that play a crucial role in heatstroke-related deaths.

The research team discovered that the anterior hypothalamus, which serves as the brain's primary temperature-regulating center, undergoes severe structural damage during heatstroke. This damage is found to be a key factor in the fatal outcomes associated with heatstroke.

“The study establishes that the anterior hypothalamus undergoes critical structural damage during heat stroke, making it a central driver of fatal outcomes. The injury in the hypothalamus can be used as definitive evidence in the forensic diagnosis of heat-stroke deaths,” said lead author Dr Ashok Kumar Rastogi, forensic expert, in a statement.

The finding can be a major step forward in the scientific basis for diagnosing heat stroke deaths through post-mortem examination, an area that has often posed challenges for autopsy surgeons in establishing a definitive cause of death, the researchers said.

It will also help address a long-standing medico-legal issue, particularly in the context of compensation, insurance claims, and death benefits for the families of victims.

How Was The Study Conducted?

The study was conducted by the Department of Forensic Medicine at AIIMS Patna in collaboration with the Department of Anatomy and Pathology.

The study was based on detailed post-mortem investigations of individuals exposed to extreme environmental conditions in the Patna region during 2024, including temperatures reaching 48 degrees Celsius, humidity levels up to 95 per cent, and prolonged heat exposure lasting five to eight hours, the Institute said.

The results also outlined a vascular injury pattern associated with fatal heat stroke, helping build a clearer pathological profile of the condition under extreme heat exposure.

The researchers noted that the findings could strengthen forensic investigations and support more scientifically grounded death certification in suspected cases.

Heatstroke is a medical emergency with a high case fatality rate. The body’s inability to regulate internal temperature and eliminate heat gain in such conditions increases the risk of heat exhaustion and heatstroke.

Speaking to HealthandMe, Dr. Naval Vikram, Professor, Department of Medicine, at the AII India Institute of Medical Sciences (AIIMS), explained how heat stroke affects people.

“The general features of a patient with heat stroke are: first, his or her body temperature will be very high. It will not be around normal levels like 104, 105, or 106—it will be significantly elevated. Second, the person may be delirious, confused, or even in a state of unconsciousness or coma. The breathing will also be labored. These are the features of heat stroke,” Dr Vikram said.

The most vulnerable category for heat-related problems is the extremes of age—the younger children and older adults. The expert noted that younger children may not be able to express their symptoms completely. They may not be able to tell you exactly what they are feeling.

At the other end, older adults often have multiple health issues—neurological conditions, diabetes, hypertension, and kidney problems.

How Can One Prevent?

Try to avoid exposure to extreme heat as much as possible.

Adequate hydration is key.

One must cover the head and upper body, use an umbrella, stay hydrated, and take breaks in between.

If you have to work in a hot environment for a couple of hours, take a break in a cooler or temperature-controlled environment for at least half an hour before resuming, rather than continuously working in the heat.

Recent photographs of former US President Donald Trump with the UK’s King Charles III have drawn attention after visible discoloration was observed on his left hand, raising fresh questions about his health.

While Trump’s right hand has appeared discolored in earlier public appearances—a concern previously downplayed by both the former president and the White House—the latest images show similar changes on his left hand as well.

“Trump's right hand has been in bad shape for a long time now, but this picture taken today shows discoloration on the back of his left hand," independent journalist Aaron Rupar wrote on social media platform X.

Speaking to HealthandMe, Dr. Amit Prakash Singh, Consultant - Internal Medicine at the CK Birla Hospital, Delhi, explained the possible underlying causes that can result in hand discoloration. He noted that the condition may be due to:

• Bruising (bleeding under the skin)

This appears as blue, purple, or black patches. It may occur due to minor trauma or sometimes even spontaneously. The use of blood thinners or antiplatelet agents like aspirin can increase the likelihood of bruising. With age, blood vessels become more fragile, making bruising more common.

• Low oxygen or poor circulation

• Swelling (fluid buildup in tissues)

• Infection or inflammation

Dr. Singh advised people "to be concerned if there is sudden swelling in one hand, severe pain or tightness, persistent blue or black discoloration, breathlessness, fever with redness and warmth, or numbness and weakness".

"A purple or blue patch often suggests bruising, blue fingers may indicate circulation or oxygen issues, puffy hands suggest fluid retention, and red, hot swelling points toward infection," the expert said.

However, there is no official medical update on the discoloration in Trump's left hand. Therefore, any claims remain speculative. But it is not the first time that various speculations have been going around about the health of Trump.

Also read: Heat Stroke or Heat Exhaustion? AIIMS Doctor Explains Key Symptoms, How To Prevent

In an interview with The Wall Street Journal, in January this year, the US President informed that he takes aspirin doses more than his doctors recommend, and that is the reason for the bruising seen on his right hand. He has repeatedly said that his health is in "excellent" condition.

In the interview, he said, "They say aspirin is good for thinning out the blood, and I don't want thick blood pouring through my heart."

Trump, now 70, was diagnosed with chronic venous insufficiency, a condition that occurs when veins have trouble moving blood back to the heart. He also showed signs of bruising on his hand, which many attributed to frequent handshaking and to the use of aspirin.

Aspirin may still be considered for some people under 60 or 70 who have a higher risk of heart disease, but this decision should be made carefully. Factors like high blood pressure, high cholesterol, diabetes, smoking history, or a strong family history can influence whether aspirin makes sense for an individual.

With temperatures rising sharply, experts at the All India Institute of Medical Sciences (AIIMS) have warned that young children are significantly more vulnerable to heat stress than adults, urging parents to take preventive measures and recognize early warning signs.

Despite morning showers offering some relief, the national capital still recorded temperatures close to 40°C.

How Extreme Heat Affects Young Kids

Shefali Gulati, Professor, Department of Pediatric Neurology at AIIMS, highlighted that children are predisposed to both heat and cold stress and also tend to get dehydrated more quickly. She noted that global temperatures have been rising over the past few decades, and cited 2020 data from UNICEF, which showed that 76 per cent of children under 18 in South Asia—around 460 million—are exposed to extremely high temperatures, with 83 or more days in a year exceeding 35°C.

Dr. Gulati explained that young children often exhibit early behavioral changes when affected by heat. These can include irritability,

• reluctance to engage in outdoor activities,
• restlessness,
• excessive sweating,
• uneasiness,
• weakness.

She added that heat exposure, when combined with air pollution, can worsen health conditions, particularly in children with lung diseases and asthma.

“Heat can affect all parts of the human body. It begins with irritability and can progress to exhaustion,” she said.

In more severe cases, heat stress may lead to brain exhaustion, loss of consciousness, seizures, dehydration, and electrolyte imbalance.

Dr. Gulati further explained that the human body maintains its core temperature through physiological mechanisms, but these are less efficient in young children. During dehydration, increased blood flow to the skin reduces supply to vital organs like the brain. In patients with pre-existing kidney issues, this can result in acute or chronic injury.

Children with conditions such as cerebral palsy and other neurological disorders may also experience worsening symptoms due to heat exposure.

Further, dehydration can additionally strain the cardiovascular system, thickening blood and leading to tachycardia, thereby affecting cardiac function.

Beyond children, pregnant women exposed to extreme heat may face risks such as preterm birth, neurodevelopmental problems, and cognitive issues in newborns.

Dr Gulati emphasized the importance of fluids, Oral Rehydration Solution (ORS), and small, frequent meals, along with reduced outdoor activity. Preventive measures include wearing loose clothing, avoiding direct sun exposure, and limiting outdoor activities during peak heat hours.

The Importance of Diet: Avoiding Sugary Drinks

Also read: Heat Stroke or Heat Exhaustion? AIIMS Doctor Explains Key Symptoms, How To Prevent

Parmeet Kaur, Chief Dietitian at AIIMS reiterated the importance of proper hydration, food safety, and dietary habits during extreme heat, warning that both children and adults face increased risk of dehydration and related complications.

“One has to avoid consuming extra sugary and salty foods, drinks, and snacks, because if one is consuming highly processed drinks or snacks loaded with sodium and sugar, it may lead to dehydration,” Kaur said.

"Hydration is key, and one should not wait to feel thirsty," she added, stressing the need to consume home-made and simple food.

For immediate management, homemade Oral Rehydration Solution (ORS) can be used, prepared with six teaspoons of sugar and half a teaspoon of salt in one liter of water.

However, she cautioned "against sugary drinks and packaged snacks like chips, explaining that high sugar and sodium content can worsen dehydration while giving a false sense of energy. While these products may create the impression of quick rehydration or an instant energy boost, they can instead contribute to greater fluid loss and increase the risk of severe dehydration.”

Instead, the expert recommended traditional cooling options such as bael sharbat, lassi, sattu, and gond katira. Ingredients like coriander, mint and onion were also suggested as part of summer dietary practices.

The dietician advised small, frequent meals that are easy to digest, including roasted and unsalted chana or peanuts, while avoiding heavy meals.

Food safety is another major concern during the summer. High temperatures increase the risk of microbial growth in stale or improperly stored food.

Kaur warned to "not consume food left at room temperature for more than two hours", as it can lead to microbiological growth. Sprouts were also flagged as potentially risky in hot weather.

Further, the expert also urged for "high heat cooking method with vegetarian food to be cooked at around 70°C, while non-vegetarian items require temperatures between 70°C and 80°C".

The expert reiterated the need to

• maintain hydration levels of approximately 2.5 to 3 liters per day.
• ensure electrolyte balance,
• take preventive action before body temperature rises.