Table 4.
Biochemical findings in patients with N2O-myeloneuropathy
| Test (units) (reference range) | Among all patients | Among those with no suspected or known previous supplementation | ||
| Median (IQR) | Number (%) abnormal according to hospital reference range | Median (IQR) | Number (%) abnormal according to hospital reference range | |
| B12 (pg/mL) (187–911) | 191 (150–246.5, n=99) | 53 (53.5%) below | 176 (148–229, n=81) | 49 (60.5% below) |
| MMA (µmol/L) (0–0.42) | 2.98 (0.62–5.84, n=41) | 32 (78.0%) above | 3.07 (0.70–5.49, n=28) | 23 (82.1%) above |
| Homocysteine (µmol/L) (0–16) | 77.5 (21.6–95.3, n=20) | 16 (80.0%) above | 82.2 (21.6–108.0, n=16) | 13 (81.3%) above |
| Hb (g/L) (women 115–165; men 130–170] | 139.0 (130.5–149.8, n=66) | 6 (9.1%) below | 138 (129–150, n=51) | 4 (7.8%) below |
| MCV (fL) (80–101) | 91.8 (89.5–94.6, n=64) | 4 (6.3%) above | 92.0 (89.9–94.9, n=50) | 2 (4.0%) above |
Biochemical tests in patients with N2O-myeloneuropathy in all patients as well as in patients with no documented prior B12 supplementation. The reference ranges displayed in the table are the broadest reference ranges used between centres; full details of reference ranges are in online supplemental table 2).
Hb, haemoglobin; MCV, mean corpuscular volume; MMA, methylmalonic acid; N2O, nitrous oxide.