High potassium but normal everywhere else?

Question

I went in for my results with a new doctor, and I was told that I have high potassium and asked if I ate a lot of bananas. I dont eat a ton but I do eat them. He said my kidney function was fine and that Im one of those people that my body doesnt process potassium very well and to cut down to half a banana every couple days. I think theres more to this than bananas. My count is 6.7 and it should be 3.5.

Im fit and work out every 2 or 3 days. I know that Ive always been sensivitve to salt as a bottle of V8 will snd me with crushing pain in my right side and into the hospital with what they beleive is kidney stones. (Allergic to the ivp) Is there something else I should look at? Could it be that the test was done wrong? I clenched my fist through the whole thing and if the test is done wrong it can read wrong results.

Answer 1

THE TEST IS ONLY AS GOOD AS THE SAMPLE!!! It is very common to have specimens sent to the lab that are not obtained properly. Red blood cells contain a LOT more potassium than plasma - so if the person that drew your sample had a hard time getting it - or if the person handling your sample did not handle it properly the little Red Blood Cells could have been damaged causing all the potassium to be released into the plasma. This is called hemolysis. Ofen the sample appears red instead of yellow and usually the lab rejects the sample or reports that hemolysis was present. Even a small amount of hemolysis will cause a falsely elevated potassium. Another common error is obtaining the sample and then putting it in the wrong tube and then discovering the error and transferring the sample to the correct tube. Unfortunately this would still contaminate the sample. These kinds of errors are often made by doctors office staff that have had no training on good laboratory practices. I would strongly recommend having the test repeated. A 6.7 is very high and I wouldn't ignore it. Too much or too little can create heart problems. Also - 3.5 is kind of on the low end. 4.5 is juuuusssst right.
Also - potassium is readily excreted by the kidneys - so drinking plenty of fluids will help you get rid of potassium. In fact, with your kidney stone problem - you should develop a habit of drinking a lot more water and maybe cranberry juice. Someone else might have better ideas on kidney stone prevention - not my area.

Answer 2

Generally speaking,
The normal range for potassium is usually considered to be 3.5-5.0 so it shouldn't necessarily be 3.5 - too little potassium is just as bad as too much.

Potassium is present in an abundant supply within cells so any activity or condition which would tend to rupture cells would send potassium freely into the bloodstream.
"Working out" is one such activity because it tends to break down muscle cells.
Relative to the fist clenching, if this action was requested of you, the likely intent of it was to remove blood from the muscle and put it into the venous system (to plump up the vein for an easier puncture). A sustained clench (muscle contraction) could mimic the effects of "working out", but the potassium content from the cellular disruption would be more concentrated in the blood as it was being drawn directly into the blood tube.
I would suggest the test be repeated.

I don't believe your doctor honestly believes the results to be accurate or he/she would be doing some serious follow-up inclusive of sending you to either a nephrologist (for kidney function evaluation) or a cardiologist (to determine if your heart function has been affected). A 12-lead EKG would likely show if your elevated potassium level (hyperkalemia) was legitimate.