How the Diagnosis Is Made
Reviewed by CDE Mehandi Sharma · Updated
The first part of the diagnosis is straightforward. A blood sugar measurement, repeated and confirmed, establishes that the baby has diabetes. Ketones are usually checked at the same time, because many babies are already unwell when they are found.
The second part is what makes this condition different from any other diabetes diagnosis: establishing the cause.
The rule is simple and internationally agreed. Diabetes diagnosed before six months of age should always lead to genetic testing, because at that age it is almost never Type 1 and almost always caused by a single gene. Many centres extend that to nine months, since the boundary is not absolute.
You may also see these tests done along the way:
- C-peptide, which shows how much insulin your baby's own pancreas is producing.
- Antibody tests, which are usually negative and help rule out the autoimmune form.
- Blood salts and acid levels, to assess how unwell the baby is and guide immediate treatment.
- Measurements of birth weight, length and head circumference, which carry genuine diagnostic information here.
The genetic test itself does not delay treatment. Insulin is started immediately while the sample is sent and processed.
If nobody has mentioned genetic testing to you, ask. It is the single most important question in the first weeks — see questions to ask the medical team.