At the beginning of each session, the results are more similar between the capillary and the sensor when obtained in the 1st week of use, as well when obtained in patients with a BMI < 24.9 kg/m2, in patients who lose less than 2 l in the ultrafiltrate, in the absence of anemia (Hb ≤ 12 g/dl). Here, GSTM1 is linked to anemia.