More on direct potentiometry--the ion-selective electrode vs flame photometry.
D001322:Autoanalysis; D006801:Humans; D011188:Potassium / Q000097:blood*; D011199:Potentiometry / Q000379:methods*; D012016:Reference Values; D012964:Sodium / Q000097:blood*
D012964:Sodium; D011188:Potassium