CRP and Hypocalcemia: Four of 49 FCM subjects (8.2%; 0% serious) who had nadir PO43− below 1 mg/dL had a potential clinical sign of HP (increased C-reactive protein [CRP], fatigue, hypocalcaemia, elevated white blood cell value, swollen finger, tingling in hand) vs. 8.0% (126/1569) with 1–<2.0 mg/dL (0.5% serious), 9.2% (113/1229) with 2.0–<2.5 mg/dL (1.5% serious), and 10.2% (411/4032) with ≥2.5 mg/dL (2.3% serious).