5th April 2024

Investigations

Diagnosis is made by measuring serum phosphate concentrations. Renal function, serum calcium, PTH levels, thyroid function tests and vitamin D levels provide useful information. As haemodialysis removes phosphate, if the patient is on renal replacement therapy, the timing between the last dialysis sessions and sampling is important. 

High calcium and phosphate levels with increased vitamin D levels indicates vitamin D intoxication.

Marked hyperphosphatemia with hyperkalemia; hyperuricemia and hypocalcaemia suggests tumour lysis syndrome.  

In rhabdomyolysis, serum uric acid and creatinine kinase levels are elevated while in tumour lysis syndrome, there is markedly raised serum uric acid but normal or slightly elevated creatinine kinase.