Nine Pints: A Journey Through the Money, Medicine, and Mysteries of Blood

Begin Reading

Table of Contents

About the Author

Copyright Page

Thank you for buying this

Henry Holt and Company ebook.

To receive special offers, bonus content,

and info on new releases and other great reads,

sign up for our newsletters.

Or visit us online at

us.macmillan.com/newslettersignup

For email updates on the author, click here.

The author and publisher have provided this e-book to you for your personal use only. You may not make this e-book publicly available in any way. Copyright infringement is against the law. If you believe the copy of this e-book you are reading infringes on the author’s copyright, please notify the publisher at: us.macmillanusa.com/piracy.

To the National Health Service

Blood makes me feel so much better, and once I’ve had blood I want to play with my toys again.

—Owen Porter, 10

Ministry of Information trailer promoting blood donation, 1946

ONE

MY PINT

There is a TV but I watch my blood. It travels from a needle stuck in the crook of my right elbow, the arm with better veins, into a tube, down into the clear bag that is being hugged by a cradle that rocks then jerks, agitating its contents, stopping the clotting. Rock and wiggle. Rock, then wiggle.

I am giving away almost a pint, and it feels like it always does: soothing and calming. I watch the bag fill with this red rich liquid, which amounts to 13 percent of my blood supply.¹ I am comforted to know that 9 pints—8, now—of this stuff is moving around my body at any time at two to three miles per hour, taking oxygen to my organs and tissues, removing carbon dioxide, keeping my heart going, keeping me going.²

People have different rates of flow so the machine beeps with alarm when the output is too low. Today mine has been acceptable. Once, my veins were judged too small and I was turned away by the National Health Service Blood and Transplant (NHSBT), and I was insulted as if the rejection were moral, not medical. For a material that has been studied for thousands of years, blood still manages to run from rationality, even at walking pace.

Donating doesn’t take long. I’m done in ten minutes. Female, A pos, time bled 11 a.m. Now I’m due to get thanked. Gratitude is the main theme here: the Wi-Fi password is thank you. This is the main donor center in Leeds, my hometown and a city of three quarters of a million people. A bright, well-staffed place on one of the biggest shopping streets. Over the road at Red Hot restaurant, you can buy all you can eat from any cuisine in the world, all at once. One hundred dishes. Here, you can lie back and do not much—though clenching your buttocks helps keep your blood moving—and help three people, all at once. Give blood, and your donation can be separated by NHSBT, the public health agency that operates blood and organ transplant in England, into several lifesaving, life-enhancing gifts. By gifts they mean components such as red blood cells, platelets, plasma, and other useful fractions. Such details are available in NHSBT literature, as are phrases like date bled. In the early days of the blood service, there were bleeding couches. But now the straightforward language of biology has changed to one of altruism. It’s all donation and gift. The reality of it, that I am emitting a bodily fluid in public, is contained as much as possible, and not just in clear plastic bags.

Once decanted into its container, my blood is on its way to becoming something that even when given for free can be brokered and sold like ingots or wheat. It is also immediately much more perishable than it was in my veins: even when mixed with a storage medium, red blood cells have an official shelf life of between thirty-five and forty-nine days, depending on local laws.³ They last longer than milk but not as long as cheese. This fragile but powerful substance can become a medicine, a lifesaver, and a commodity that is dearer than oil. Yet I give my blood freely because I know that my body will soon replace it and other people need it. I want nothing in return but a mint biscuit, a cup of tea, and a sticker that reads BE NICE TO ME. I GAVE BLOOD TODAY.

*   *   *

Every three seconds, somewhere in the world, a person receives a stranger’s blood. Globally, 13,282 centers in 176 countries collect 110 million donations. The United States transfuses 16 million units of blood annually; the UK, 2.5 million. All of this blood is given to people when they have cancer or anemia or when they give birth; it can assist equally in trauma or chronic disease. Some accident victims can receive 60 units of blood; a liver transplant patient can use 100, or several bodies-full. A newborn can be saved with a teaspoonful. Read about the modern use of blood, and the word precious or special will appear alongside health care resource. Economists call the sale of organs and body parts a repugnant market. But blood is different. The movement of blood—a body part, after all—is accepted unquestioned and common enough to be banal. But it is wondrous, still. It is as wondrous as blood.

Poor Odysseus. Deep in Hades, surrounded by ghosts and wraiths, and his mother won’t speak to him. Not until she drinks the blood that Odysseus has taken from reluctant sheep. For Homer, blood had a power as fierce and invisible as electricity: a mouthful of blood, a switch flicked, and Anticlea could now speak to her son.⁴ Of course Homer was awed by blood. There is nothing like it. It is stardust and the sea. The iron in our blood comes from the death of supernovas, like all iron on our planet.⁵ This bright red liquid—brighter in the arteries, when it is transporting oxygen around the body from the heart, duller in the veins, when it is not—contains salt and water, like the sea that we came from.

We no longer sacrifice humans or beasts but the force of blood remains in language: blood feud, blood brothers, bloodlines. It remains in metaphor, where blood becomes an emotional state: my blood can be chilled, boiling, curdled. And its force remains in reality: most people associate the cheating cyclist Lance Armstrong with his abuse of erythropoietin (EPO), a hormone that stimulates the body to make more red blood cells. But I can’t shake the image of him with a fridge full of his own blood, removed from his own body and ready to be transfused back into it.⁶ A dose of fresh blood gives a cyclist enough strength—more red blood cells mean more oxygen—to push harder up the mountain, or an athlete to run faster around a track. The World Anti-Doping Agency includes blood on its list of prohibited substances, whether the transfusion be autologous (someone reinfusing his or her own blood), homologous (someone else’s blood), or heterologous (blood from another species).⁷

The mythical Gorgon Medusa, with her head of snakes, showed the two-faced nature of blood best: the veins on her left side contained blood that was lethal, while the right side gave life. Transfusions can be two-faced, too. The right type of blood can save your life; the wrong one can kill you. I am calmed by the sight of my blood when it is being drawn or when I scratch it out from under my skin. I also curse it: along with stray menstrual tissue, it has wandered around my body for years to where it shouldn’t be, so that I am riddled and glued by the adhesions of endometriosis, and every month they bleed too, in cacophonous sympathy.

We fear blood, still, despite our science and understanding, and we look to blood to tell us who we should fear. In 1144, the death of a young man named William of Norwich was attributed to Jews who had crucified him in order to use his blood as a sacrifice. This was the first documented case of what became known as blood libel, and it was enduring and lethal: for centuries, blood libel was used as a reason to massacre Jews and steal their property, across northern Europe, again and again.⁸ In 2015, a Hamas leader in Gaza declared that Jews were still killing children and using their blood to knead into special Passover bread. The Times of Israel headlined this MEDIEVAL MINDSET.⁹ I consider modern bans of gay men donating blood—the prohibitions are being relaxed now but persist—and see fear, not science. People with HIV are still jailed for not disclosing their status to sexual partners, long after HIV has become treatable to the point where it is not contagious. Chlamydia and hepatitis, now more life-threatening or disabling, get no such sanction. Blood is what artists still use to shock, although increasingly the menstrual kind.

Examine my blood with the right tools, and it can reveal who I am and what I was and what may become of me. I set up an alert to gather any mention of a simple blood test, and it brings me news that my blood can be tested to show my biological or chronological age; whether I am likely to develop Alzheimer’s, Parkinson’s, or various types of cancer; whether surgery will give me delirium; whether my heart is failing; whether I am concussed. Most of these tests are still possibility and hope, or years away from being available. But already blood is a surveillance camera, the widest window with the best view into my past, present, and predictable future. Blood is one of the three main diagnostic tools of a doctor: the others are imaging and a physical exam.

Perhaps Hollywood describes blood best. In 1957, Frank Capra made a film for television. It was part of a series of educational films sponsored by Bell Laboratories; the year before, Capra had made The Strange Case of the Cosmic Rays, using puppets of Dostoyevsky and Dickens. In that context, his next film was perhaps normal. It was an extraordinary, partly animated portrayal of how blood moves around the body and what it does, its star a muscular cartoon he-man who, like the film, was named Hemo the Magnificent. He was blood, and he was magnificent with an attitude to match his muscles. You men in white coats, Hemo said with disdain to the two human actors playing Dr. Research and A Writer, as Hemo stands surrounded by forest creatures (I didn’t say it made sense), you are not fit to tell my story.

Humans think blood means disease, wounds, pain. These friends (the animals) they know me for what I really am: health, life. I’m the song of the lark, the blush on the cheek, the spring of the lamb. I am the precious sacrifice ancient man offered up to his gods, I am the sacred wine in the silver chalice. Down through the ages I am the price men pay for freedom. But to you scientists, I am a smear on a slide, a stain, a specimen, a sickness. My story is a song only poets should sing, not disease-lovers.¹⁰

I’m wooed by this, as much as his cooing animal chorus. (I’m less convinced by the analogy of vascular sphincters to railroad switchmen.) But my Yorkshire plain-speaking soul likes another description, from a consultant working for NHSBT. Blood, she said, is the stuff that spurts out when you are not very well.¹¹

*   *   *

The spleen is popular. Someone suggests the pancreas. Another offers, The heart? No one is sure, now that they have been asked. No one knows where blood is made.

The answer is: bones, mostly. Inside the bone, in the marrow, which most people probably think of as dog food, but which is the essence of us. Gosh, says a hematologist when I tell him no one ever guesses this. I wonder what they think the bone marrow does.

Perhaps they think bones are white and brittle, not vivid and vital. Perhaps they believe blood circulates ready-made, unchanging. Blood is always dying, always renewing, and rapidly: you can’t yet grow back an arm, but you can lose plenty of blood and survive. The bone marrow produces two million red blood cells every second. It produces pluripotent stem cells that can become any cell, and red blood cells with no nucleus that can slink and slither through the tiniest of capillaries. Images of red blood cells show filled-in Cheerios or enticing pillows, so when I see a simulation of red blood cells, I want to jump into the picture and curl up in the middle of one. The American Society of Hematology prefers to liken them to doughnuts.¹²

Daily, the blood’s thirty trillion red cells do a full circuit of the body, traveling about twelve thousand miles, three times the distance from my front door to Novosibirsk. The circulatory system of veins, arteries, and capillaries is about sixty thousand miles long, twice the circumference of the earth and more. Most of that is the capillaries, tiny blood vessels and holloways that reach nearly every cell in the body. In a resting human, the heart pumps a liter of blood every ten seconds, and it beats seventy-five times a minute. So does the heart of a sheep. A blue whale’s heart, the size of an economy car, beats five times a minute (less on a deep dive); a shrew’s, one thousand times.¹³ The heart is busy, and so is blood. It has a lot to do. It carries oxygen to organs and tissues, as well as nutrients, heat, and hormones, the signals that regulate our functions, energy, sleep, mood. It carries out waste disposal, ridding the body of carbon dioxide and other unwanted matter. It clots when necessary. It fights infection and repels foreign invaders. It is a tissue and an organ at once. The heart, a hematologist tells me, is a pump for circulating our most important organ. Blood does all this—feeding station, temperature control, waste disposal, defender—and it never rests until you are dead.

Blood has fascinated humanity since it first spilled. Yet much about this amiable juice, as Goethe called it,¹⁴ remains remarkably mysterious. Take type. There are the four that you’ve heard of: the ABO group of A, AB, B, and O. Then the rhesus factor that makes you positive or negative. All blood is categorized according to antigens, molecules found on the surface of red blood cells and on antibodies in plasma, the liquid part of blood. All blood cells have H antigens on their exterior, then A and B groups add A or B antigens or both. They are signals and markers: if a blood arrives in the body that has different molecules, it will be recognized and rejected. It is a highly effective alarm system. A and B will accept O because it has H antigens like they do. But an A type would reject a B type and vice versa. O negative has no A, B, or rhesus antigens, so anyone can have it. Every emergency department fridge will have O negative blood in it.

Get blood types wrong and the meeting of bloods will cause clots and clumping. The body can go into degrees of hemolytic shock, producing symptoms that range from itching to death.

In countries with good blood supplies, this is rare: the UK regards an incorrect blood transfusion as a never event, something grave with serious consequences that was preventable. In 2015, never events included part of a chisel being left inside a patient, a fallopian tube removed instead of an appendix, and a B-positive person given A-positive blood, a mistake that was made clear by the patient getting chest pain and fever. The following year, there were three wrong transfusions (out of 2.5 million units transfused) but 264 near misses.¹⁵ Globally, the chances of a transfusion-related infection are smaller than they have ever been. In poor countries, the prevalence of hepatitis B in blood is 0.3 percent; in a high-income nation, it’s a tenth of that.¹⁶

The International Society of Blood Transfusion lists thirty-six blood group systems, and ABO is only one. Probably there are more like three hundred. Some more: Lutheran, Kell, Lewis, Duffy, Kidd, Diego, Dombrock, John Milton Hagen, Indian, and Globoside.¹⁷ Most groups are named for the person who discovered them, so I’d quite like to meet Yt, Xg, and the cheerful Ok. One group is named Landsteiner-Wiener partly for Karl Landsteiner, the Austrian biologist who wondered why some blood mixed with other blood would clump and in 1901–3 discovered that not all blood was alike, that there were types and differences.¹⁸ He later grouped blood into A, B, and C (later changed to O). It was an extraordinary discovery that won him the Nobel Prize, has enabled millions of people to be safely transfused with blood from perfect strangers, and I hope brought him more happiness than he publicly conveyed (photographs of him range from stern to terrifying). Perhaps his grimness came from his knowledge that he didn’t know what blood types were for. We still don’t.

Not that science hasn’t been very busy. We can now change B-type blood to O type using an enzyme from a coffee bean (which clips off the B antigens from cells, leaving them nice and O). We have discovered that blood types can correlate with geography or ethnicity or a particular threat. Forty percent of Caucasians have type A blood, but only 27 percent of Asians.¹⁹ The fact that O-type people are more susceptible to cholera was first noticed in 1977. During Peru’s 1991 epidemic, people with O blood were eight times more likely to be hospitalized.²⁰ People from the Ganges delta, where cholera has always been endemic, have the lowest rate of O type anywhere. Recent research has shown that the cholera toxin thrives in intestinal cells derived from O-type stem cells, causing more severe infection.²¹ In very bad news for A and AB men, a group of Turkish urologists recently found that their risk of erectile dysfunction was considerably increased compared to O-type men.²² O-type people have a better chance against malaria while Bs come off worst. Ups and downs. These findings are inklings (a word nothing to do with writing but meaning to utter in an undertone). Why we have blood types, why they developed differently in different places at different times: we can still speak theories only in an undertone, not with certainty.

Yet in most countries, including mine, only mothers and patients and soldiers know what blood type they are. On a Portuguese warship, once, I stared in wonder at my escort’s name badge, because under his name was his blood group. Pedro, A. I never got used to this. To know the sailors’ blood types seemed wrong, as if I were reading on their name badges their latest sperm count or what their girlfriend best liked them to do in bed. It seemed prurient, invasive, like seeing inside them.

This is not rational. Common sense and blood sometimes repel each other. The Nazis, obsessed with the purity of blood, decided A was Aryan; B was inferior.²³ The Japanese even now believe that blood type involves far more than what antigens are on the outside of each blood cell. A types are perfectionist, kind, calm even in an emergency, and safe drivers; Bs are eccentric and selfish, but cheery. Os are both vigorous and cautious while ABs, obviously, are complicated.²⁴ A book on blood types in beautiful women was a bestseller, along with the author’s follow-up, a book on blood types relating to lunch boxes.²⁵ Blood typing has serious consequences: people are denied jobs because of it and it is thought necessary to making a good dating choice. In 2011, when government minister Ryu Matsumoto resigned a week after taking office, having offended survivors of Fukushima and the earthquake, he blamed his blood type. My blood is type B, he told reporters, which means I can be irritable and impetuous […] My wife called me earlier to point that out.²⁶ Blood type discrimination somehow nicely slots in with perceptions of inferior minorities: AB and B, more common in Taiwanese and Ainu people, are thought to be violent, backward, and cruel.

Cold War Americans thought blood type so important that they tattooed it onto adults and children. It would come in handy after the bomb dropped, when one physician predicted a city the size of Chicago would require nearly a million pints of donated blood.²⁷ In northern Indiana, wrote the historian Susan E. Lederer, using a Burgess Vibratool instrument with thirty to fifty needles and an antiseptic ink, technicians tattooed the blood type and Rh factor on the chest of some 1,000 residents at the county fair.²⁸ Operation Tat-Type went on to tattoo children at five elementary schools, before the program was dropped because doctors didn’t trust tattoos to be a fail-safe indication of blood type.²⁹ An editorial writer in Logan, Utah, reminisced about these smudgy reminders that can still be seen on middle-aged natives, though not read.³⁰

The idea that blood is more than biology is not new. Nor is it resolved: blood is classified differently in different countries and even in the same country by different authorities. The UK exempts it from the Human Tissue Act, although it is a tissue, having cells. The United States thinks it a biologic. The World Health Organization (WHO) added blood to its list of essential medicines (which even poor countries are advised to stock) only in 2013. In a lab in a London hospital, a man in a white coat moves away from his microscope and lets me see. It is nothing exciting for him, but it is the first time I have seen blood cells. The blood has been stained to be visible on the slide, so I can see clearly: the red cells, those biconcave discs, dumbbells and doughnuts. So vivid, though in a human body some are always dying and being replaced. I am my sixth version of myself, if most of my cells are replaced every seven years,³¹ but I’m on my 143rd round of red blood cells, which live for about 115 days.³² There is a popular philosophical question about identity and self, named Theseus’s ship or Theseus’s paradox: If all the planks were replaced in his vessel, was it still his ship? If I have replaced many of the cells I was born with, and none of the red blood I had at Christmas, am I still me?

When men first started to move blood between one body and another, they thought that they transmitted spirit with it. Transfundere, to pour from one vessel into another. A Mister Acton, writing in 1668 after the early transfusionists had published experiments, thought one experiment most remarkable because it was the Transfusion of the Blood of a Mangie dog into a Sound one, to try whether the mange would be communicated with the blood. The Mangie dog was cured; and the other who had received his blood, not become Mangie.³³ As blood was thought to cure spirit, not sickness, it was taken from suitable animals. Calves, lambs, mild and quiet creatures, were thought to transmit their sweet spirit to the frenzied and the troubled.

We can laugh at this, but we will be laughed at in turn. Our knowledge of blood is wide and unfinished.

*   *   *

Find yourself a blue coat first. There are plenty in the cupboard that look grubby but smell clean. Then sit on the bench provided and put your hair in a bonnet, something like a shower cap, and wrap your shoes in plastic. Follow the instructions above the basin and wash your hands thoroughly. No, more thoroughly. That’s enough: they relaxed the restrictions a few years ago so you no longer have to wrap your beard or wear a snood. The pressure chamber now: this arrangement will be familiar to anyone who has been to a bank or traveled on a submarine. You step in and wait for one door to close before the other can be opened. The higher pressure of the air beyond keeps dust and bugs out. Now you have passed from the gray zone to the white zone. Now you are safe to walk onto the processing floor of the largest blood facility in Europe.

Today’s bleed is 2706. Every day except Sunday, beginning just after lunch, one thousand gallons of blood arrive here from a several-hundred-mile radius, from many generous arms and veins. Filton is a small town in southwest England but also the name of this £60 million ($84.4 million) facility run by NHSBT, which processes a third of the blood donated in England. Getting here took months of asking. Nor I am allowed to identify or quote anyone. This is frustrating when the people I meet there are human and colorful beneath their white coats and plastic bonnets: along a corridor near the café there are photographs of staff in their leisure hours, and there is a diver, a knitter, a canicross competitor, and a newt collector. That’s just one wall. But I understand why the NHSBT guards itself so tightly: the nation’s blood is a vital and sensitive resource, and you wouldn’t want just anyone coming to visit. Between the blood leaving me and entering someone else—a process known as vein to vein—an awful lot is done to it.

Blood arrives by vehicle and in bags. The plastic bag that I saw my blood running into is packed along with nine others into a blue cooler like a picnic bag. In the same bag are samples, three from each donation. All is put on a conveyor, and the donations go one way and the samples another. Testing is done at the same time as processing. All donations are tested, but Colindale, one of the three processing sites, doesn’t have testing faculties, so Filton gets theirs too. Four thousand tests a day. Blood groups, obviously: ABO but also rhesus factor. Then, syphilis, HIV, hepatitis B, C, and E. First-time donors are also tested for human lymphotropic virus, which can cause leukemia. Particular donors, depending on where they have traveled or what they have done to their body with sharp implements—tattoos trigger a four-month deferral—can be tested for malaria, Trypanosoma cruzi (which causes Chagas’ disease), West Nile virus, or cytomegalovirus. Anyone who has traveled to somewhere with Zika is currently deferred for twenty-eight days. For now. Tests can change. New infections come; others die away. Zika has been known about since the 1970s, but it wasn’t expected to cause trouble. White blood cells are removed from all donations—a process called leukodepletion—because it is in white cells that many infections travel, including the prions that cause variant Creutzfeldt-Jakob disease (vCJD), a vile and violent affliction that anyone growing up in the 1980s will visualize as piles of burning cattle and skeletal humans who fall when they walk because their brains are degenerating.

Safe. A blood system that is safe. Governments repeat this as if it can be true, not aspirational. But safety is a relative concept. Blood is a biological product and can never be safe because we can’t plan for the next Zika or Ebola or HIV, until it comes.³⁴

The processing space at Filton is vast, with a simple color scheme. The blue-coated staff and the red of the blood. There it is, hundreds of bags, hanging from hooks on what is called an overhead filtration device but what resembles a giant chicken rotisserie. It looks like a vampire’s feast, and though the blood is safely contained in its bags, the color shouts through the sterility and bonnets and lab coats: this is not an inert material. Vivid, from the Latin. To live, to be living. Leukodepletion is being done by drip and filter: as the rows of bags rotate, the larger white blood cells are filtered out and the rest collects in the bottom of the bag.

Then anything can happen. Depending on need and logistics, a donation can become several useful products. Filton produces red blood cells, fresh frozen plasma (used for burn victims and to replace lost blood volume), platelets (used for clotting and by cancer patients), cryoprecipitate (also used to aid clotting), and leukodepleted whole blood, used for infants. Everything is organized and logged on a computer system, which obviously is called Pulse.

When Filton was being designed, NHSBT consulted the car industry. It was going to be an industrial process, and they wanted to have the most efficient production lines, like any industry. Like cars. The processing room was initially divided into three long lines, like a car production line. But it didn’t work. This complicated business requires supervision, and supervisors were having to walk too far. Now the floor is set up in pods: small areas organized by a one-way flow system. A donation of leukodepleted whole blood comes in, it is processed by smart machines and dizzying technology, and it leaves at the other end of the pod as something else. If something goes wrong in a pod, a maximum of 96 units has to be quarantined, not the whole flow. All donations are centrifuged with considerable force, to separate plasma from the rest. Staff remember a hole in a bag—a manufacturing fault—and the power of the centrifuge throwing blood around the pod, with vigor. The humans got out of the way and off lightly: they changed their lab coats and got back to work.

The rest of the processing involves clever machinery and lots of tube connectors running between blood and bags. There is pressing and freezing and filtration and separation. It is technical and complicated and I must be starting to look the way I feel, because my guide asks kindly if he has fried my brain yet. It’s not his fault. He does his best to translate. At various points I encounter equipment described as a giant condom or a snow globe. I am warned about lumps and clumps. I’m invited to look for platelets in a processed bag and advised to spot swirls, like a sprat in an ocean shoal of fish, seen from a plane. I see the sprats—I wouldn’t from a plane, unless they were the size of a ship—and they are pretty. By the end of all this, I know that platelets look nothing like sprats, that if any donation is out of its allotted temperature for half an hour, it must be thrown away, and that anyone who complains that a unit of standard red blood cells costs £124.46 ($177.64) has no idea what a bargain they are getting. That is the price no matter what the blood group. Filton also processes blood groups so rare, they are kept frozen for ten years in an NHSBT facility in Liverpool. Plasma is cheaper, at only £28.75 ($40.39) a unit. Other products are costlier: some cryoprecipitate is £1,113.45 ($1,564.08) a unit.

In 2012, Filton flooded. Luckily, it was a Monday. No donations are taken on a Sunday, so nothing was being processed. A Friday night would have been awful. Other good times would have been during the Olympics, major football matches or sporting events, national holidays, Christmas, summer holidays, and Easter: these all badly affect blood donor numbers. The flooding could have been disastrous: all processed red blood cells must be kept in fridges at 39.2 degrees Fahrenheit until the test samples have cleared and they can be released from quarantine. Plasma is frozen from fresh—and called fresh frozen plasma—and kept that way until it is used.

That is, male plasma. Away from the pods and the processing, my guide shows me some cages. They are filled with bags of plasma that should be yellow but isn’t always. My plasma, probably, is green. I’m female and menopausal and taking hormone replacement therapy, and all those factors—along with the contraceptive pill—turn women’s plasma green. Off and odd-looking. They don’t know why, and it doesn’t really matter, as all female plasma is discarded anyway, since NHSBT introduced a policy of male donor preference in 2003. It is believed—though evidence is inconclusive—that antibodies produced by pregnant women can attack the lungs of anyone who reviews that plasma. Binning it is easier.

There are other conditions as well as being female that can turn plasma into a discard. My guide searches through the bags before he finds one with triumph. This is a nice one. I peer at it. Look, he says. Fat. I see globs of fat floating among the golden plasma. Staff are required to inform a donor if his or her blood is alarmingly fatty, even when the bag’s appearance may just be the result of a fat-laden pre-donation meal. Obesity threatens life like HIV does. Perhaps now HIV is treatable, fat is worse. None of the NHSBT videos about Filton mention the discards. I don’t mind if I become medical waste: the rest of my blood is useful. Discards used to be incinerated, but that was expensive as well as unsettlingly Old Testament. Burned blood. Now it gets alternative treatment, which my guide thinks is a form of fancy landfill.

The blood products that survive discard can be processed in twenty-four hours. By six p.m. each day, donations set off for their destinations. Filton serves ninety hospitals with regular deliveries but sometimes the hospitals need irregular ones. In that event blood can go by taxi, a bag on a front seat like a passenger. At even odder hours, a fleet of volunteer bikers might deliver blood. I find a captivating Pathé film from 1967 about a Volunteer Emergency Service, which involved young motorcyclists zooming around London transporting blood as a charitable enterprise. This was probably to do with Father Bill Shergold, known to his flock as Farv, and an East End priest who thought bikers—generally despised and feared by the public—could be modern knights, upholding ideals of courage, courtesy, and chivalry. When Farv was seventy, and retired, he was approached by Wrangler to star in its advertising. Shergold asked his rector if that was acceptable, and the rector replied, Of course you must do it. Good for the Church to be seen doing ordinary, rather silly things. Ordinary and rather silly, too, was the idea of doctors at Plymouth Hospital in the 1970s that blood samples could be delivered by carrier pigeon. The idea and the pigeons did not take off.³⁵

I can’t discover what happened to the Volunteer Emergency Service, but blood bikers are thriving and vital. The Nationwide Association of Blood Bikes and its regional chapters deliver thousands of blood bags a year, for nothing. They also deliver breast milk, spinal fluid, surgical instruments, and fecal matter for fecal transplants. Their slogan is Saving Lives and Money, and, as their publicist writes on the Blood Bikes site, despite many of us being middle aged and a bit flabby, they are doing more and more deliveries and getting more recognition. As this is Britain, the recognition often consists of free hot drinks in certain cafes [and] nods and waves from police and paramedics.

Normally, blood that has been bled—Filton uses more corporeal terminology than the donor center, with its donations and gifts—arrives all day from one p.m. until eleven p.m. The quickest turnaround is blood that can be issued by one p.m. the next day. Donations from first-time donors take longer: they have to go through the testing twice, for extra safety. For this reason, blood bankers like two types of donors: young ones and ones that come back. They always sound desperate for both. A nation-state needs 1 to 3 percent of its population to give blood to maintain an adequate blood supply,³⁶ the higher the better. The UK needs two hundred thousand new donors every year. This should be blood from voluntary non-remunerated donations because this is the type of blood supply that the WHO thinks is safest. People who aren’t paid for blood don’t generally lie about their health. But of 172 countries surveyed by the WHO, 80 reported that only 1 percent of the population was donating. That’s not enough. In Africa, the WHO judges that most countries in the region do not have enough donors for a safe or adequate blood supply.

Seventy-one countries get more than half of their blood from family replacement systems (where patients are encouraged to provide blood given by relatives) or paid blood sellers. I have grown up in a country with one of the best and safest blood supplies in the world. I have been spoiled. The scientific wizardry of Filton; the efficient blood donation and delivery system. That is not how much of the world gets its blood.

*   *   *

It is easy to wander the corridors of Delhi’s major hospitals, unmolested by staff or security. The corridors of Safdarjung Hospital, one of the city’s largest, are usually full and noisy, and even my obviously foreign face provokes no interest. People have their own troubles.

In law, India’s blood supply is rigorously monitored and a voluntary system. This fiction is as flimsy as paper. Countries that can find enough donors or sellers to meet their blood requirements are in a minority. In fact, India relies heavily on a family replacement system. Patients who require blood must supply blood from a relative or friend. Upstairs, at the hospital blood donor center, I meet a young man who is donating blood for his pregnant wife. It is his first time donating, and he says he’s not nervous, but when the needle goes in he bares his teeth. With this suffering, he will get a blood credit of one unit for his wife to use if need be. This is how the United States’ blood supply began and why we talk of blood banks. Bernard Fantus, then director of therapeutics at Chicago’s Cook County Hospital, invented the concept of blood banking. Blood storage was already being done by then, but it was Fantus who thought up debt and repayment of blood, who saw blood as a product to be transacted, not a gift. He was straightforward about this, saying in 1937 that "just as one cannot draw money from a bank