Table 1.
Test | Staging | FPIR | Insulin secretion | Insulin sensitivity | Beta cell function | Disease progression risk | Limitsa |
---|---|---|---|---|---|---|---|
Dynamic tests | |||||||
Standard OGTTb | ✓ | ✗ | ✗ | ✗ | ✗ | ✓ |
• Invasiveness • Age limit ( 7–8 years) |
Extended OGTTc | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
• Invasiveness • Age limit ( 7–8 years) |
MMTT | ✗ | ✓ | ✓ | ✓ | ✓ | ✗ |
• Invasiveness • Age limit ( 7–8 years) |
IVGTT | ✗ | ✓ | ✗ | ✗ | ✗ | ✓ |
• Invasiveness • Age limit ( 7–8 years) |
Hyperglycaemic clamp | ✗ | ✓ | ✓ | ✓ | ✓ | ✗ |
• Invasiveness • Age limit ( 7–8 years) |
Euglycaemic–hyperinsulinaemic clamp | ✗ | ✗ | ✗ | ✓ | ✗ | ✗ |
• Invasiveness • Age limit ( 7–8 years) |
Static tests | |||||||
Urinary C-peptide-to-creatinine ratio | ✗ | ✗ | ? | ✗ | ✗ | ? |
• Invasiveness • No age limit |
HbA1c/fasting glucose | ✗ | ✗ | ✗ | ✗ | ✗ | ✓ |
• Invasiveness • No age limit |
C-peptide capillary dried blood spot test | ✗ | ✗ | ? | ✗ | ✗ | ? |
• Invasiveness • No age limit |
Risk indices computed during OGTT | |||||||
DPTRSd | ✗ | ✗ | ✗ | ✗ | ✗ | ✓ |
• Invasiveness • Age limit ( 7–8 years) |
Index60e | ✗ | ✗ | ✓ | ✗ | ✗ | ✓ |
• Invasiveness • Age limit ( 7–8 years) |
Other | |||||||
CGM | ✗ | ✗ | ✗ | ✗ | ✗ | ✓ |
• Invasiveness • No age limit |
a relatively low, very low, relatively high, very high
bStandard OGTT: glucose is measured at 0, 1 and 2 h
cExtended OGTT: glucose, insulin and C-peptide are measured at multiple time points (seven or more) and the test can be prolonged up to 240 min. Early sampling (e.g. 10 and 15 min) allows FPIR to be estimated
dDPTRS= (1.57 × log BMI) − (0.06 × age [years]) + (0.81 × glucose summed from 30 to 120 min/100) − (0.85 × C-peptide summed from 30 to 120 min/10) + (0.48 × log C-peptide0)
eIndex60 = 0.36953 × (log C-peptide0 [ng/ml]) + 0.0165 × glucose60 (mg/dl) - 0.3644 × C-peptide60 (ng/ml)
CGM, continuous glucose monitoring