Potassium 5.9 mEq/L

No — 5.9 mEq/L is above the normal range (hyperkalemia). It is usually not an emergency at this level, but it deserves a prompt call to your clinician, a repeat test, and a medication review.

Yes, and it happens often. Red blood cells hold enormously more potassium than the liquid part of blood, so if cells rupture during the draw — from a small needle, a tight tourniquet, fist pumping, or rough handling of the tube — potassium spills out and inflates the result. Labs usually flag these samples as "hemolyzed." It is the single most common reason for an unexpectedly high potassium in someone who feels well, and a carefully repeated draw settles the question.

Most US hospitals treat potassium below about 2.5 mEq/L or above about 6.5 mEq/L as critical (panic) values, and many also flag anything at or above 6.0. But danger is not just the number: how fast the level changed, whether your heart or kidneys are already strained, and medicines like digoxin all shift the picture. That is why an identical number can be routine for one person and an emergency for another — your clinician interprets it in context.

Food helps with mild dips, but it has limits: a medium banana holds about 420 mg of potassium — roughly 10 mEq — while treatment for a genuinely low level often requires far more, in prescription form, along with fixing whatever is causing the loss. Beans, potatoes, leafy greens, citrus, and yogurt are all richer sources than most people expect. Never take large doses of over-the-counter potassium on your own; the dose and follow-up testing should come from your clinician.

Not for this value by itself. It belongs in a conversation with your clinician — same-day for clearly abnormal results, routine for borderline ones — but if you ever develop palpitations, chest pain, marked muscle weakness, or trouble breathing alongside an abnormal potassium, seek emergency care regardless of the number.

Plenty of common ones do. Medicines that raise potassium include ACE inhibitors (lisinopril), ARBs (losartan), spironolactone and other potassium-sparing diuretics, NSAIDs (ibuprofen, naproxen), and the antibiotic trimethoprim. Medicines that lower it include thiazide and loop diuretics (hydrochlorothiazide, furosemide), insulin, albuterol inhalers, corticosteroids, and overused laxatives. Potassium-based salt substitutes and supplements push levels up, sometimes sharply in people with kidney disease. Never stop or change a prescription because of one lab value — bring the list to your clinician and adjust together.