You must be using a different measure to the one we use in Oz, - 5.1 would be extraordinarily high on our scale.
The US uses grams/deciliter to measure phosphate; the UK and ex-dependencies (
) millimol/litre
So, 5.1 g/dl is equivalent to 1.7 mmol/l
Oh I wish my PO
4 were so low — it was 3.2 mmol/l (9.6 g/dl) last month