The normal range for potassium is 3.7 to 5.2 mEq/L.
Not all hyperkalemic patients require the Full Monty treatment package including calcium insulin, glucose, beta-2 adrenergic agonists, diuretics, sodium bicarbonate, cation exchange resin and dialysis. There's a continuum of treatment which becomes more aggressive as the K gets higher, symptoms of hyper-K are manifest, EKG changes develop and the rate of rise increase.
Generally speaking,
1. K above 7.0, severe muscle weakness or marked EKG changes require immediate, aggressive treatment
2. K around 6.5 in asymptomatic patients with no EKG manifestations of hyperkalemia can be treated with a cation exchange resin
3. K < 6 can often be treated with a low K diet, +/- diuretics.
In all cases, find and reverse the underlying cause.
Source
Rose, B. "Clinical manifestations and treatment of hyperkalemia" Up to Date. 16 April 2008.