Tests recommended for investigation of hypoglycaemia/hypoglycaemia screen
| Test | Sample requirements (can vary—confirm with your laboratory) | Metabolic/endocrine conditions screened for by this test | Collection at the time of hypoglycaemia | Notes |
|---|---|---|---|---|
| Glucose | Blood Fluoride oxalate | All | Essential | To confirm genuine hypoglycaemia |
| Insulin and C peptide | Blood Serum | Hyperinsulinism (including factitious) HIHA | Essential | Will require immediate freezing—discuss with laboratory. Intraosseous samples not suitable |
| Free fatty acids/NEFA | Blood Fluoride oxalate | Hyperinsulinism (low) | Essential | |
| 3HB/ketones | Blood Fluoride oxalate | Hyperinsulinism (low) Fatty acid oxidation disorders (low) Ketogenesis defects (low) Ketolysis defects (high) | Essential | Ratio of FFA/3HB indicative of disorder of FAO or ketone metabolism |
| Organic acids | Urine | FAOD Organic acidaemias | Essential | Ideally collect the next urine passed |
| Blood gas | Blood | Organic acidaemias Causes of lactic acidosis | Preferable | |
| Lactate | Blood Fluoride oxalate | Glycogen storage disorders Gluconeogenic defects Mitochondrial disease | Preferable | |
| Amino acids | Blood | Organic acidaemias Liver dysfunction | Preferable | |
| Ammonia | Blood | HIHA | Preferable | |
| Growth hormone | Blood Serum | GH deficiency Hypopituitarism | Preferable | Low levels of GH at the time of hypoglycaemia warrant liaison with endocrinology and further confirmatory testing |
| Cortisol | Blood | Adrenal insufficiency Hypopituitarism | Preferable | F/U short Synacthen test±VLCFA in boys |
| Acylcarnitines | Blood/DBS | FAOD Organic acidaemias | Not essential | |
| Thyroid-stimulating hormone | Blood | Hypopituitarism | Not essential | Interpret with caution in sick children and in conjunction with other pituitary tests |
| Liver function | Blood | Liver failure (including metabolic causes such as galactosaemia, tyrosinaemia type 1, mitochondrial disorders) | Not essential | |
| Renal function/electrolytes | Blood | Adrenal insufficiency | Not essential |
3HB, 3-hydroxybutyrate; DBS, dried blood spot; F/U, follow-up; FAOD, fatty acid oxidation defects; GH, growth hormone; HIHA, hyperinsulinism-hyperammonaemia syndrome syndrome; NEFA, non-essential fatty acids; UCED, urea cycle enzyme defects; VLCFA, very long chain fatty acids.