Background: Absolute neutrophil count (ANC) below 1.5 G/l or 1 G/l is commonly used as a factor to determine the decision to administer antineoplastic treatment including chemotherapy and novel agents to cancer patients. This practice is based on observations that below this ANC, there is an increased risk of bacterial and fungal infection. This is further based on the assumption that this parameter always correctly reflects the true shortage of these germ-fighting cells in patients. In reality, the circulating pool of neutrophils is only one of four reservoirs (bone marrow, circulating, marginal and tissue pools) and its size is influenced not only by shortage but also by transient shift of cells between these reservoirs. The aim of this study was to evaluate whether repeated blood collection affects ANC in the patient.
Methods: We retrospectively analysed the medical records of cancer patients with 0.8 G/l ≤ ANC < 1.5 G/l in whom CBC was repeated based on the physician's decision, which was done on the same day roughly 2 h after the first one.
Results: The patients at the time of repeating CBC had consumed breakfast. In 31 out of 32 patients, ANC exceeded 1 G/l or 1.5 G/l and antineoplastic treatment was administered as originally planned. There were no infectious complications observed.
Conclusion: Cancer patients should not be fasting prior to blood collection, with the exception of special and rare situations. To achieve the maximum clinical benefit, delays and/or reductions of antineoplastic treatment should be avoided wherever possible. Pseudoneutropenia is an unnecessary reason for postponing chemotherapy.
Keywords: Antineoplastic treatment; Hydrocortisone test; Neutropenia; Prednisone test; Pseudoneutropenia.