Sunday, March 27, 2011

What's In A Number?


It’s my habit to send all patients a copy of their laboratory evaluation, along with a summary of the important findings and recommendations. It’s not practical to discuss every value in a short letter (but of course, I am happy to meet with patients to do so). For patients who like to do their own research, the New York Times has an excellent interactive guide: http://www.nytimes.com/interactive/2008/09/29/health/20080929_BLOODEXAM.html.

Even as I spent a lot of time discussing lipid profiles and the value of cardio-CRP levels with my patients, these are not my favorite tests. Analyzing some of the less glamorous assays can provide valuable clues to health and potential medical problems.

If I could run only one profile in my patients under 40, it would be the complete blood count. The absolute numbers are helpful; the ratios are even more so. Is my patient eating properly? Are there potential genetic problems we need to investigate (sickle cell trait, thalassemia)? Is my patient abusing alcohol, steroids or over the counter medications? Are environmental allergies a problem? Any parasites from that exotic vacation?

After age 40, I would add the comprehensive profile (Chem 24). These tests screen the liver and kidneys, which over time can start to show some wear and tear. We can see the cumulative effect of eating a less than perfect diet, consequences of medication (both ethical pharmaceuticals and non-medical), infection and metabolic disturbances.

Other tests can be very helpful for individual patients, and there always seems to be a test du jour. These days, I am ordering a lot of Vitamin D levels. There is a move to cut back on the number of PSA’s, and homocysteine is completely out of fashion. Unfortunately, there is no one test that can predict (or even diagnosis) disease. As I tell my patients – if such a test existed, wouldn’t everybody order it?

No comments:

Post a Comment