Diagnostic biochemical investigations
| Value | Reference range | |
| Hyperprolinaemia type II | ||
| Plasma (μmol/l) (n = 5) | ||
| Proline | 2290–2900 | 89–281 |
| Hydroxyproline | 6–90 | < 10 |
| Ornithine | 131–145 | 27–103 |
| Urine (μmol/mmol creatinine) (n = 5) | ||
| Proline | 3700–47500 | < 13 |
| Hydroxyproline | 85–420 | < 13 |
| Glycine | 1432–4055 | < 356 |
| Ornithine | 18–33 | < 8 |
| N-(pyrrole-2-carboxyl)-glycine | Present | Not detected |
| Vitamin B6deficiency | ||
| Plasma (nmol/l) (n = 2) | ||
| Pyridoxal phosphate | 23.5; 22.7 | 24.3–81.0 |
| Pyridoxic acid | 1.0; 2.7 | 10.9–27.3 |
| Urine (μmol/mmol creatinine) (n = 1) | ||
| Pyridoxic acid | 0.4 | 0.5–2.3 |
| Urine (μmol/mmol creatinine) | ||
| Basal (reference) | Peak | |
| Tryptophan load test | ||
| Xanthurenic acid | 12.4 (0.3–1.5) | 3165.91-150 |
| Kynurenic acid | 2.5 (0.8–3.0) | 524.91-150 |
| Kynurenine | 3.1 (1.1–3.7) | 545.51-150 |
| 2-Aminoacetophenone | Not detected | Present1-151 |
Plasma vitamin B6 was measured by high performance liquid chromatography (Dunn Nutrition Centre, Cambridge; department of clinical biochemistry, Glasgow Royal Infirmary). Tryptophan metabolites and pyridoxic acid were measured in urease treated extracted urine by gas chromatography mass spectrometry with single ion monitoring. Basal values are compared with in house paediatric reference ranges.
↵1-150 Reference is less than 10-fold increase above basal;
↵1-151 Not reported