It's two in the morning and the platelet count didn't move. You gave a full adult dose, ABO-compatible, straight off the agitator, room temperature the whole way, and the post-transfusion count looks almost identical to the pre-transfusion count. The reflex is to order more platelets. Sometimes that's right. Often it isn't, and knowing the difference is the entire point of this post. You cannot adjudicate refractoriness without a post-transfusion count This sounds obvious wri

Somewhere in this patient's chart, someone typed "IgA deficient." That's it. No level, no antibody status, no history of a reaction. Just the label. And because the label exists, an order goes in for washed red cells and IgA-deficient plasma, every time, for the rest of this person's transfusion history, because that's what you do when someone is IgA deficient. Except I'm not sure any of us fully know what we're protecting against. What actually counts as IgA deficient, for u

The blood supply is short again. It's short often enough that "short" undersells it, this is closer to a chronic condition than an emergency. So the question comes up, reasonably, from patients, from colleagues outside the field, sometimes from residents who assume someone must have solved this by now: why can't we just make blood? The honest answer is that people have been trying for over a century, and it's worth being clear-eyed about why before getting excited about where

A patient is partway through a routine therapeutic plasma exchange. The replacement fluid has been albumin the whole way through, as it usually is. But as the procedure nears its end, the last exchange volume gets switched to 2 units of FFP to "finish" the procedure. Nothing about the patient's clinical picture changed in that last liter. The switch happens because ending an exchange on plasma feels safer than ending it on albumin, even though nothing about the math supports

A patient shows up needing blood. Her antibody screen comes back positive for something rare, something we can find antigen-negative units for, but not easily, and not fast. The question on the table isn't "is this antibody there." It clearly is. The question is: will it actually hurt her if we transfuse anyway? This is the part of transfusion medicine that doesn't make it into the textbooks as often as it should. We're very good at detecting alloantibodies. We are, frankly,

In 1961, a blood bank in Melbourne ran a routine antenatal work up on an Aboriginal Australian woman and got a result that didn't make sense. Her red cells reacted with nothing. Not the anti-D, not the anti-C, not the anti-E; every reagent in the Rh panel came back negative, as though the entire Rh system had simply been left out of her blood. It had. She was the first documented case of Rh-null, the phenotype that would later earn the nickname "golden blood." Sixty-some year

In the past two weeks I've published two blogs about stories that arose around blood type: the one piece of biology we all happen to know about ourselves. This got me thinking about why humans love stories so much, and led to this post. During the V-1 bombing campaign of 1944, Londoners became convinced the Germans were sparing certain neighborhoods. The bombs seemed to cluster, hitting some districts again and again while leaving others conspicuously untouched. The explanati

In Japan, it is entirely normal to be asked your blood type on a first date. Dating profiles list it next to height and occupation. Some employers have, at various points, sorted job candidates by it, on the theory that Type O makes a better leader and Type A makes a better accountant. There is a specific term for this: ketsuekigata, blood type personality theory. It has no biological mechanism, no supporting evidence at scale, and roughly fifty years of cultural staying powe

A friend at a dinner party once turned down the bread basket because she was "type A, and grains don't agree with her blood." I nodded, passed the butter, and spent the rest of the meal thinking about lectins instead of listening to the conversation. Occupational hazard. The blood type diet has been around since 1996, when naturopath Peter D'Adamo published Eat Right 4 Your Type [1]. Its premise: your ABO blood type reflects your ancestors' diet, so eating in accordance with

The patient is a composite, built from enough cases to be nobody in particular: an elderly man admitted with a colonic obstruction, febrile, blood cultures eventually growing a gram-negative rod. His chart says A positive. It has said A positive for decades, through two prior admissions and one prior transfusion. The type-and-screen that comes back this time says otherwise. The forward type shows both A and a weak but unmistakable B reactivity. The reverse type, his own serum

Families who request directed donation from an “unvaccinated” donor believe they are choosing the safer option. The literature says the opposite. Directed donations, particularly from first time donors recruited specifically for the occasion, carry higher rates of infectious disease marker reactivity than units from repeat community donors. The donor pool people trust the most, because they know the person, is measurably less safe than the anonymous pool they're trying to avo

I knew Wisconsin had hard water before we moved here — everyone warns you about the white crust that builds up on faucets, the way soap won't quite lather right, the kettle that needs descaling every few weeks whether you want to deal with it or not. What I didn't expect was how much I'd find myself thinking about it on a quiet Saturday afternoon, half-bored, half-curious, turning over a question I hadn't really asked before: does any of this actually do anything to me? Hard

Microplastics are having a moment. They've turned up in blood, in placentas, in breast milk, and, most alarmingly, in a 2024 NEJM paper that's done more to shape the public conversation than almost anything else in this space, in carotid artery plaque, where their presence correlated with a higher rate of cardiovascular events. Here's what's actually established: microplastic particles are measurably present in human tissue and blood, and we absorb them through what we eat, w

The call comes in from oncology. Their patient — a fifty-something with metastatic melanoma, two months into pembrolizumab — has been confused for three days. Low-grade fever. Can’t tell you the year. Can’t tell you where they are. Infectious workup negative. LP unremarkable. MRI with some FLAIR signal in the mesial temporal lobes. They started high-dose IV methylprednisolone 48 hours ago and the patient isn’t better. Neurology thinks it’s ICI encephalitis. Oncology wants to

There was an attending I worked with as a fellow who had a habit. Patient looks fluid overloaded, hemoglobin is borderline-low-ish, reach for a unit of red cells. The logic, stated out loud more than once: it'll help pull some of that fluid back into the vessels. Oncotic pressure. It made physiologic sense in the moment, the way a lot of things in medicine make sense until you actually look up the numbers. I looked up the numbers. What oncotic pressure actually is Oncotic pre

A patient calls the clinic the morning of their appointment. Their ride canceled. Again. The scheduler offers to rebook, but the patient hesitates — they've already canceled twice this month for the same reason, and they're starting to wonder if the clinic thinks they just don't want to come in. They do. They just can't get there. I've heard versions of this story enough times recently that it stopped feeling like a string of coincidences and started feeling like a pattern. T

In 2008, an FDA advisory panel sat down with a meta-analysis that pooled thirteen randomized trials of cell-free hemoglobin-based oxygen carriers — HBOCs, for short — and found that, as a class, these products increased the risk of myocardial infarction and death compared to controls. Within the year, the FDA had effectively frozen HBOC development in the United States. Almost two decades later, the freeze hasn’t really lifted. One of the products caught in it, Hemopure, has

The system is collapsing. Before we try to save it, we should ask whether it was working. Something Has Changed Something has changed in academic publishing. Papers I submit take longer to get reviewed than they used to. Desk rejections — the kind where a paper doesn’t make it out to reviewers at all — feel more common. When a review does come back, it sometimes arrives months after submission, accompanied by an apology from an editor who clearly struggled to find anyone will

It’s two in the morning. Your pager goes off. A nurse tells you her patient spiked a fever — 38.4°C, up 1.2 degrees from baseline — about two hours into a unit of packed red cells. She stopped the transfusion and is waiting for your call. You work it up. DAT negative. Plasma clear. No hemoglobinuria. No respiratory distress. No hypotension. The patient’s mildly uncomfortable but gets better with acetaminophen. In the morning you write it up: febrile non-hemolytic transfusion

The pager goes off. The message reads: “Bloodless surgery consult — patient refusing blood products.” If you are a transfusion medicine fellow and this is your first one, you probably spend a moment staring at your pager wondering exactly what you are supposed to do with that information. You show up, introduce yourself, and are handed a form. It is several pages long. At the top, in clear block letters: WHOLE BLOOD COMPONENTS. Below that, a list of products — red blood cells