Table 1:

Results of laboratory investigations for a 17-year-old man presenting with thirst, lethargy and fatigue over a one-month period

Test (normal values)	Results
Ionized calcium, mmol/L (1.17–1.33)	1.45–1.50
24 hr urine calcium, mmol/d (1.2–6.2)	4.5
24 hr urine creatinine, mmol/d (5.0–16.0)	13.0
Serum creatinine, μmol/L (45–97)	66
25-hydroxyvitamin D (< 25 nmol/L, deficient; < 75 nmol/L, insufficient; > 250 nmol/L, toxic)	40
Parathyroid hormone, pmol/L (1.3–7.6)	5.5–10.3
Serum phosphate, mmol/L (0.90–1.45)	1.21
Calcium-to-creatinine clearance ratio	0.008–0.009