VENOUS BLOOD SAMPLING Blood samples will be obtained via a 17G venous cannula inserted into the other forearm. Samples will be taken hourly on 10 occasions from −1h (beginning of the inulin/PAH infusion) to 8h; a total of 120 mls will be taken. Blood will also be sampled at 24h (09.00 on day 3) and 72h 09.00 on day 5); 24 ml at each time.