Table 1.
Reproducibility of the modified sequential solid phase extraction procedure for measurement of 13N-labelled metabolites in blood
| 13N-glutamate | 13N-ammonia | 13N-glutamine | 13N-urea | |
|---|---|---|---|---|
| Coefficient of variation (%) | 1.5 (0.1–7) | 7.7 (0–28.9) | 11.2 (0.1–42.5) | 17.9 (0–57.3) |
Data are shown as mean and range of coefficients of variation between two measurements of 13N-fractions in blood samples taken 1–30 min after intravenous administration of 500 MBq 13N-ammonia to 5 cirrhotic patients without HE (Fig. 2). For each metabolite the lowest value is from the 1-min time point and the highest value from the 30-min time point