1. Bad Blood

I was brought upstairs from Emergency to Intensive Care and given a treatment called apheresis.

From the Greek: aphairein, to take away.

In the hematological context, apheresis is the process of separating blood into its components (red cells, white cells, platelets, plasma), removing the component that’s sick, and reinfusing the rest of it, along with a suitable replacement for the sick part. The sick part of my blood was the plasma.

My nurse told me about a man she treated whose body manufactured too many platelets, enough to clot his blood right in his blood vessels. And so when his blood was separated, the extra platelets were removed and thrown away, and replaced with saline to make up the lost blood volume.

I thought his platelet-producing powers might have been made useful—if his extra platelets could flow out of him, through an apheresis centrifuge, and right into a hemophiliac.

But of course the man’s genes might have been diseased, or he might have been infected by a secret virus, and his platelets might have given someone his disease, or worse. So they were just collected in a bag and thrown away.

My plasma was filled with an antibody that destroyed peripheral nerve cells, so it was thrown away, too.

My plasma was replaced more than fifty times, and the effects of the treatment lasted as long as the fresh plasma stayed clean of the anti­bodies, which for several months was only about two days.

The machine took four hours to clean my blood. I bled eight ounces into the centrifuge, then the ­machine spun the blood fast enough to separate it into four layers. My plasma flowed into a bag, then my cells were mixed with saline, synthetic albumin (a blood plasma protein), and fresh frozen plasma (containing the other plasma proteins). That new mixture was re­infused. And then the machine withdrew another cup and did the same thing, and then another cup, and so on, until the new plasma occupied enough blood volume that it was no longer useful to withdraw and clean another cup.

The first twenty times or so, ­before I had a central line—a tube in my chest that provided easy access to my blood—my arm veins were used for blood collection and reinfusion.

I received direct injection, via tubing connected to a cannula, or hollow needle—no flexible catheters were inserted. I had to lie still so the needles didn’t tear my veins. Fourteen-gauge needles were used, one in each crook of my elbow—one to take blood out and one to put it back in.

Routine blood draws, which I had several times a day, are taken via...