I take the same spot in the lot every time, the one closest to the door on the highway side, because after eighty visits some decisions stop being decisions and just become the thing you do. It's not long past opening, a Thursday. The lot is a third full, mostly regulars, as it always is before the walk-ins arrive at lunch and triple the wait.

Kira's at the front desk again. She says my name before I get my card out. "Marek. Eighty-one." She says it the way you'd read off a batting average, like the number is doing some of the talking for her, and I tell her I'm not going for a personal best, and she gives me the laugh she gives everyone and slides the clipboard across even though I could recite the questions from memory by now. Have you traveled outside the country in the last three months. Have you gotten a tattoo or a piercing in the last three months. Are you currently taking any prescription medications.

I write no, no, and then I stop on the third one, because a month and a half ago the true answer changed and I haven't been in since it did.

I write it anyway. Clopidogrel. Started a month and a half ago. The pen hovers for a second — it's a strange thing to feel caught by a line on a form I've filled out this same way for years — but the form asks and I answer honestly, as I do most things, and it's not as if a word on a clipboard has ever stopped me before. The iron supplement I was briefly on didn't. The blood pressure medication I took for two years and then came off didn't. I hand the clipboard back the same as always and take my seat to wait for my number.

I started giving because a company I worked for ran a drive in the parking lot one October, a bus with the seats taken out and cots bolted where the seats had been, and I went out on my lunch break mostly because a coworker asked and I didn't have a good reason to say no. I gave whole blood a handful of times after that and then somebody at a different drive, years later, told me my veins ran well for the machine and asked if I'd ever tried platelets, and I said I hadn't, and that was most of it. Nobody recruited me with a speech. Nobody told me what it would add up to. I just kept being available on the days I was available, and the days simply added up, until a woman at a front desk could read a number off a screen like a batting average and I could believe her without checking.

The waiting room smells like it always smells, coffee and hand sanitizer, and the television in the corner is muted as always, and across from me a woman I don't recognize is filling out her first-timer paperwork with the careful, slightly worried handwriting of someone doing this for the first time. I remember being her, in a way I can't fully reconstruct anymore. Eighty visits ago I read the same pamphlet about vasovagal reactions she's reading now, with the same private conviction that it wouldn't apply to me, which turned out to be true, mostly, except for the one time in year three when it wasn't.

They call me back before her, because I'm a scheduled apheresis appointment and she's a walk-in whole-blood slot, and the two lines move at different speeds through the building even though they start in the same chairs.

Priya's doing intake today. I've seen her maybe a dozen times over the years — always steady, never the kind who narrates what she's doing while she does it. Cuff on my arm, the squeeze and the release, the number she reads off without comment. Thermometer under the tongue. The finger stick for the hemoglobin check, that quick flat sting and then the bead of blood drawn up into the little tube like it's being poured instead of pulled. She reaches the weight field and leaves it open, because this is normally the point when I stand on the scale and today she has stopped before getting that far.

I know what comes after this part as surely as I know a route I've driven eighty times. They'll walk me back to the room with the machines, run the line, and somewhere in the first few minutes I'll get the tingle in my lips and fingertips that means the citrate's doing its job faster than my body is clearing it, and I'll ask for the calcium chews as usual, and around the second cycle the returning blood will come back a few degrees cooler than my own and I'll feel it climb my arm like weather moving through, and near the end the machine will make the particular two-note chime it makes when the collection bag is full, a sound I could pick out of a lineup of other machines in another room. None of that is going to happen today. I don't know that yet. Priya does.

She's going through my chart on the screen and I watch her stop reading before she says anything, which is its own kind of information.

"You had a procedure," she says. Not a question.

"Stent. A Tuesday, out of nowhere." I give her the account I've given twice at the gym and once to my brother on the phone — a blockage they found and fixed with a wire and a little mesh tube, in and home the same day, back to normal inside a week. "They've got me on the clopidogrel for good. Not just while it heals. For good."

For good is doing more work in that sentence than I mean it to, and I don't notice until it's already out of my mouth.

She reads something on the screen for a second, and I can see in the set of her mouth that this is a conversation she's had before, with someone else, more than once.

"Clopidogrel's an antiplatelet," she says. "It does exactly what it sounds like — it stops your platelets from clumping together. Which is what you want, after a stent. It's keeping that vessel open."

"And also the thing you're here to collect."

"Also the thing I'm here to collect." She doesn't dress it up, and I appreciate that more than I expect to. "The deferral on antiplatelets for platelet donation runs fourteen days after you stop the medication. Whole blood is a different list — you might still clear that one, once the stent-healing window closes and depending on a couple of other things. But platelets specifically, it's fourteen days clear of the drug. Not fourteen days from today. Fourteen days from whenever you stop taking it."

I do the arithmetic before she finishes the sentence. I've been doing the same with other things ever since the cardiologist, without calling it arithmetic. Fourteen days after stopping. I am not stopping. There's no day on any calendar where that count begins, because the day it would begin is the day I go off a drug that is currently the only thing standing between me and a second stent, or worse. The clock needs a start line and there isn't one, and there isn't going to be one, and I understand this completely in about the time it takes her to finish a sentence I could have finished for her.

"So the fourteen days doesn't start now," I say, working it out loud as if confirming a route I already knew, just to hear it back. "It starts whenever I come off the clopidogrel. And I'm not coming off the clopidogrel."

"Right."

"Ever."

"For the foreseeable future, that's what they're telling you, yeah."

I ask her once. I decide on the drive in, before I even know it's coming, that I will ask exactly once and then I won't ask again, because I already know the shape of the answer. Is there a version of this where I come off it for two weeks, get the donation in, go straight back on?

"No," she says, and there's no hedge in it at all, which is its own kind of kindness. "You can't stop a prescribed medication in order to donate. Not for us, not for anybody, ever. If your cardiologist someday tells you you're off it for good, that's a different conversation, and you come back in and we requalify you. Until then, the eligibility follows the drug, and the drug doesn't come off for a donation. Not for one day. Not for us."

I nod, and I don't ask again.

There isn't a villain anywhere in this room. Priya didn't put the stent in or write the fourteen-day guideline. She isn't enjoying delivering it any more than I'm enjoying hearing it. There's nobody upstairs I could appeal to who'd tell me the rule bends for a man with eighty donations behind him, because it isn't that kind of rule. It isn't measuring me against anyone else who's ever sat in this chair. It isn't asking whether I've been good at this, which I have — every one of the eighty came back clean, every unit did what it was supposed to do for whoever needed it. It isn't asking anything about me at all. It's asking about a molecule doing its job in my blood, and the molecule doesn't know my name or my number.

"Whole blood, though," Priya says, pulling up a different screen, "we could probably clear you for that once the healing window's done, depending on a couple of things we'd have to check when the time comes. It's not the same restriction list."

"Maybe," I say, and I mean the sort of maybe reserved for a smaller thing standing next to a bigger one, not as a stand-in for it. I don't say yes and I don't say sign me up today. I don't let it become the thing that makes the rest of this all right, because it isn't a version of the same thing. It's a different thing that happens to be in the same building.

Through the doorway behind Priya I can see into the room with the machines, three of them lined up along the wall, one running, two idle with their tubing coiled and capped. A man about my age is in the far chair, connected, a magazine open on his lap that he isn't reading, his free hand resting flat on the armrest, as if to remind himself it's still his. I know exactly what he's feeling right now, the particular calm two-hour boredom of it, because I've felt it eighty times, and I'm not going to feel it again today, and there isn't a version of this morning where that stops being true no matter how long I sit in this smaller room instead.

She's quiet for a second, in the specific way people go quiet when they're deciding whether to move on to the practical part now or let a moment sit a little longer first, and she picks the practical part, and I'm grateful for it, because I don't especially want the moment sat with.

"I've got you on a callback list that reminds you every couple of weeks that you're due," she says. "I can take you off it, or I can leave it running and you just ignore the ones that don't apply, in case something changes down the line — a different medication, a doctor who clears you off this one. Some guys like to keep it going. Some don't want to see the number come up."

I think about the calls. Every other week or so, an automated voice with my name spliced into a script, telling some earlier version of me that he's overdue for something the current version of me can no longer do.

"Leave it going," I say.

She nods, types something, and the chart on the screen still has a field open, the cursor blinking where the number hasn't caught up yet to what either of us just said.

"I still need your current weight for the file," she says. "Goes in whether we collect today or not."

"It's the same as June," I say.

"I'll write it in anyway."

"Sure," I say. "Write it in."