A few weeks ago, my mother's doctor asked me to start monitoring her blood pressure. He suggested I get one of those home testers and use it to check her every few days. So I bought the best available model of what I'd heard was the leading maker of such devices — the Omron IA2 Digital Blood Pressure Monitor. I took it over to Mom's, strapped her into it…and got a reading about 20 points higher than the one her doctor had gotten when he tested her, low-tech style, the previous day.
A jump of 20 points in eighteen hours? It's possible but it didn't seem likely. I tested her every day or so for the following week and every reading was around 20 points above what it had been in her doctor's office. I began to suspect my mother wasn't malfunctioning. The machine was.
Then I had an appointment with my doctor — nothing important, just routine — and while waiting in the examining room, I noticed an Omron IA2 Digital Blood Pressure Monitor. When my doc came in, I asked him about it. "Never use 'em," he said. "They have them in all the rooms here and I don't think anyone uses them. They're always twenty points too high."
Well, that's good to know. I asked him why they were here. He said, "I don't know." But when I told him about my experiences with the one I bought, he said, "Let's test it." He took my blood pressure the old-fashioned way. Then we waited two minutes and took it with the Omron. The Omron was twenty points higher. Exactly.
When we exited the examining room, he asked one of the older doctors in his office about the blood pressure devices. The older doctor said, "Oh, those? They're always twenty points high."
"So why do we have them?"
"I've never been sure. I think Donna [whoever that is] ordered a batch of them because the clinic got a deal. Every so often, we have a nurse trainee or someone who doesn't know how to check blood pressure and they use them. But if they do, I always recheck. That's how I know they're always twenty points too high."
I asked the questions you'd ask and here's what roughly what the doctor said: "It's actually a very well-made product. In a sense, it's too good. When you take a blood pressure with one of these —" and here, he fiddled with his stethoscope like Oliver Hardy playing with his necktie "— you're listening for the brachial pulse and for an indicator called the Karotkoff sound. The machine has better hearing than any doctor or nurse so it senses those sounds much quicker and…well, that's why it's always too high." (I am, by the way, approximating his explanation from memory. If I got it wrong, forgive me…but it was something like that.)
Anyway, he went on to say that the machines are, at least, consistent. "If you use it and it shows a higher total than it did the last time, that's a good indicator than your blood pressure is going up. You just have to remember to subtract 20 if you're comparing the numbers to a blood pressure reading done by a doctor. There are machines that take that into account but they're not for home use." When I got home, I did a little Googling and found a lot of folks saying that their Omron is always 20 points too high.
Okay, so here's me being logical again. Are these machines really and truly always 20 points high? If so, I would imagine the Omron folks could fix that in about the time it takes me to adjust a bathroom scale that's always 20 pounds over. I've gotta be missing something here.
[UPDATE, a little less than two hours later: Four people have written me to say they have an Omron that is either accurate or which they hope is accurate because if their blood pressure is really 20 points lower, they're in trouble. I don't doubt theirs may be correct. But how come so many people (Google "Omron" and "20 points" and you'll see at least a dozen examples) get readings that are consistently 20 points too high?]