Table 1.
The influence of changing sample handling after venesection on OGTT plasma glucose concentrations
| Plasma glucose concentration (mmol/L) | ||||||
|---|---|---|---|---|---|---|
| Period A: delayed centrifugation | Period B: early centrifugation | |||||
| Fasting | 1 h | 2 h | Fasting | 1 h | 2 h | |
| Number | 7,509 | 7,426 | 7,415 | 4,887 | 4,812 | 4,808 |
| Mean | 4.41* | 6.99† | 6.05‡ | 4.65* | 7.33† | 6.21‡ |
| SD | 0.41 | 1.63 | 1.34 | 0.4 | 1.69 | 1.42 |
Period A: January 2015 to May 2017, centrifugation of blood samples on completion of OGTT. Period B: June 2017 to October 2018, early centrifugation of samples within 10 min of venipuncture. *t = 32.35, P < 0.0001; †t = 11.11, P < 0.0001; ‡t = 6.29, P < 0.0001.