Table 4.
Diagnostic markers for inborn errors of metabolism are applicable to screening by tandem mass spectrometry using dried blood specimens
| Disease | Markers (value of cut‐off) † | |
|---|---|---|
| Organic acidemias | Methylmalonic acidemia/ Propionic acidemia | C3 (>3.6) C3/C2 (>0.22) |
| Isovaleric acidemia | C5(>1.0) | |
| Methylcrotonylglycinuria | C5‐OH (>1.0) | |
| Multiple carboxylase deficiency | C5‐OH (>1.0) | |
| 3‐Hydroxy‐3‐methylglutaric acidemia | C5‐OH (>1.0) | |
| Glutaric acidemia type 1 | C5‐DC (>0.20) | |
| β‐Ketothiolase deficiency | C5‐OH (>1.0) C5:1 (>0.025) | |
| Fatty acid oxidation disorders | Medium‐chain acyl‐CoA dehydrogenase deficiency | C8 (>0.30) C8/C10 (>1.70) |
| Very‐long‐chain acyl‐CoA dehydrogenase deficiency | C14:1 (>0.25) C14:1/C2 (>0.013) | |
| Trifunctional protein deficiency Long‐chain acyl‐CoA dehydrogenase deficiency | C16‐OH (>0.08) C18:1‐OH (>0.05) | |
| Carnitine palmitoyltranseferase 1 deficiency | C0/(C16+C18) (>40) | |
| Carnitine palmitoyltranseferase 2 deficiency | C14/C3 (>0.3) (C16 + C18:1)/C2 (>0.5) | |
| Carnitine acylcarnitine translocase deficiency | (C16 + 18:1)/C2 (>0.55) C16 (>5.0) | |
| Systemic carnitine deficiency | C0 (<7.5) | |
| Glutaric acidemia type 2 | C8 (>0.3) C10 (>0.4) C12 (>0.4) |
†
The cut‐off levels are set at the average value ±6 SD. These levels are applied for detection of the candidate diseases as the newborn screening in the Department of Clinical Laboratory in Almeida Memorial Hospital as following the previous report. 29