Ab­nor­mal re­sults not al­ways cause for worry

Daily Freeman (Kingston, NY) - - YOUR DAILY BREAK - An­thony Komaroff AskDr.K

Last week I re­ceived the re­sults of some re­cent blood work. A few of my values fell just out­side the nor­mal range. My doc­tor says it’s fine, but I’m still wor­ried. Do I need to be?

A print­out of lab re­sults typ­i­cally in­di­cates nor­mal ranges for each blood test next to your per­sonal re­sults. If your per­sonal re­sult is right in the mid­dle of the nor­mal range, you’ll likely feel re­lief.

But what if your re­sult is at the very low or high end of nor­mal, or even slightly out­side the nor­mal range? Should you worry? Un­for­tu­nately, there’s no straight­for­ward an­swer. Here’s why.

With most blood tests, dif­fer­ent lab­o­ra­to­ries would all come to pretty much the same re­sult. How­ever, with some tests there is more vari­a­tion in the re­sults from one lab to the next.

An­other source of vari­a­tion is you. The lev­els of many mol­e­cules in our blood change, some­times from hour to hour. Blood sugar lev­els, for ex­am­ple, vary de­pend­ing on what and when we ate. Other re­sults are af­fected by how hy­drated you are. Other re­sults change with age.

The genes you in­her­ited can af­fect re­sults and may cause your re­sults on par­tic­u­lar tests to be out­side the nor­mal range ev­ery time tests are done. The ques­tion is not whether the re­sult is “ab­nor­mal,” but whether it is be­com­ing even more “ab­nor­mal.”

Re­sults that change sig­nif­i­cantly over time are im­por­tant even when a lab re­sult is nor­mal. For ex­am­ple, I had a pa­tient whose PSA test for prostate cancer was in the low nor­mal range ev­ery year for 20 years. Then, one year it was in the high nor­mal range — still nor­mal, but quite dif­fer­ent for him. I caught his prostate cancer at an early and cur­able stage.

There’s no magic about the cut­off point for call­ing a test re­sult ab­nor­mal. Just as in the man with prostate cancer, a re­sult in the nor­mal range can still be a sign of dis­ease. And re­sults that are out­side the nor­mal range (“ab­nor­mal”) don’t mean a per­son has a dis­ease.

With some tests there is dan­ger if the re­sult is ab­nor­mally high or ab­nor­mally low. With other tests, it’s wor­ri­some only if the ab­nor­mal­ity is in one di­rec­tion.

So, here’s my general ad­vice for deal­ing with lab­o­ra­tory test re­sults. If the re­sults are near ab­nor­mal or def­i­nitely ab­nor­mal, and your doc­tor says not to worry:

• Sup­pose that the re­sult has changed sig­nif­i­cantly from when it was tested pre­vi­ously. If so, ask if that change means it should be tested again sooner than usual.

• Sup­pose that the re­sult is well into the ab­nor­mal range (not just over the line), but has not changed sig­nif­i­cantly. (For ex­am­ple, if a liver test has a nor­mal range of 30-50, and your re­sult re­mains 80, that is more wor­ri­some than if your re­sult re­mains 52.) If your re­sult is way out­side the nor­mal range, ask if there are any dis­eases that the re­sult could in­di­cate, and any other tests for those dis­eases that should be or­dered.

Dr. Komaroff is a physi­cian and pro­fes­sor at Har­vard Med­i­cal School.)

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