Background/Aim: If blood tests were performed at home, unnecessary trips of patients for chemotherapy could be avoided. The HemoCue® WBC DIFF device was tested at home by 14 patients with breast cancer. Materials and Methods: A total of 42 measurements of white blood cell (WBC) and neutrophil counts with the device at home were compared to laboratory measurements performed within 3 hours. Bland-Altman plots were created for limits of agreement that should be less than 1.0×109/l for WBC and 0.5×109/l for neutrophils to indicate a similar grade of intensity. Results: Limits of agreement were -1.61×109/l and +2.34×109/l for WBC and -1.15×109/l and +1.39×109/l for neutrophils. All patients considered the device advantageous, particularly because they did not have to travel or wait for results. Most patients experienced problems with the lancet when taking blood samples. Conclusion: Disagreement of WBC and neutrophil counts between methods appeared clinically relevant. Findings need to be verified in a larger cohort, including the use of a different type of lancet.