DEAR DR. ROACH: I recently read in your column that you test your patient’s magnesium levels when they have been on long-term proton-pump inhibitors (PPIs). When I asked my doctor to include this in his order for blood tests, I was told that the test isn’t accurate, and he wouldn’t order it. Is there a special magnesium test that I can request?

When I looked it up on the internet, this is what I found: “Standard magnesium blood tests (serum) are generally not considered an accurate indicator of total body magnesium. While they can detect severe deficiency, they are unreliable for diagnosing mild-to-moderate deficiencies because less than 1% of the body’s magnesium resides in the blood, with levels tightly controlled by borrowing from bones.”

— J.B.

ANSWER: People who are on PPIs and most diuretics are at a high risk for low magnesium. It’s true that most magnesium is in the cells; however, like potassium and calcium, a low blood level does indicate that the body level is also low, and steps should be taken to keep the body from losing more magnesium.

Although there are people who need long-term PPIs, such as those with Barrett’s esophagus or those in whom tapering off PPIs has failed, my experience is that there are many people who are taking these medicines who may not need them. I am sure that they were started on them for a good reason, but most people can be tapered off the medicine after six weeks or so.

DEAR DR. ROACH: I’m 80 years old. I stopped using aspirin about six months ago after years of use. However, I saw a cardiologist after a coronary calcium score (that I asked for) suggested a problem; it showed arterial calcification of the left anterior descending artery (98). I had a normal stress test, and there wasn’t any evidence of inducible myocardial ischemia or a “high physical work capacity.”

In light of all of this, the cardiologist recommended 81 mg of aspirin nightly. Why is he recommending aspirin? It causes bruises even from soft contact with a hard object. My arms are covered with bruises.

— H.G.

ANSWER: In people over 80 without known blockages, the balance of the risks and benefits usually lands on the side of not giving aspirin. The fact that you have a calcium score of 98 (on the low side but definitely not zero) still doesn’t outweigh the bleeding risk in a person over 80. In my opinion, aspirin is more likely to cause more harm than good in your situation.

A statin drug is likely to cause more benefit and less harm, and if you aren’t taking one, I would discuss this with your cardiologist when you discuss stopping aspirin.