No associated reference range. Should be interpreted alongside with glucose and c-peptide.
Non- diabetic hypoglycaemia
Evaluation of hypoglycaemia should only be undertaken for patients in whom Whipple’s triad has been documented. Firstly, review the history and physical findings to exclude more common hypoglycaemic aetiologies such as; drugs (insulin, insulin secretagogues, alcohol ingestion), critical illness (sepsis, organ failure), cortisol deficiency and non-islet cell tumours.
Once these have been excluded, in the seemingly well individual, the differentials lie between accidental/ surreptitious hypoglycaemia and endogenous hyperinsulinaemia. Further evaluation is warranted and should involve the following concomitant tests in the event of an ongoing episode of hypoglycaemia; plasma glucose (for confirmation of hypoglycaemia), insulin, C-peptide, beta-hydroxybutyrate as well as the measurement of circulating oral hypoglycaemic agents (if there is a degree of suspicion). When spontaneous hypoglycaemia cannot be observed, a prolonged fast or mixed meal test may recreate the environment in which hypoglycaemia is likely to occur.
Table 1: Taken from the Endocrine Society Guideline in 2009
| Sxs/Signs |
Glucose
(mmol/L)
|
Insulin (pmol/L) |
C-peptide (pmol/L) |
BHB (mmol/L) |
Circulating OHA |
Ab to insulin |
Interpretation |
| No |
<3.1 |
<21 |
<200 |
>2.7 |
No |
No |
Normal |
| Yes |
<3.1 |
>>21 |
<200 |
≤2.7 |
No |
Neg (Pos) |
Exogenous insulin |
| Yes |
<3.1 |
≥21 |
≥200 |
≤2.7 |
No |
Neg |
Insulinoma, NIPHS, PGBH |
| Yes |
<3.1 |
≥21 |
≥200 |
≤2.7 |
Yes |
Neg |
Oral hypoglycaemic agent |
| Yes |
<3.1 |
>>21 |
>>200 |
≤2.7 |
No |
Pos |
Oral hypoglycaemic agent |
| Yes |
<3.1 |
<21 |
<200 |
≤2.7 |
No |
Neg |
IGF mediated |
| Yes |
<3.1 |
<21 |
<200 |
>2.7 |
No |
Neg |
Not insulin (or IGF) mediated |
