Impact of sample freezing on MBS AST-POCT results
macrohematuria
Analyses on frozen samples were performed only on culture-positive samples, i.e., on samples for which urine culture and AST results were made available by the hospital’s laboratory. Analyses were performed after 2, 5 and 7 days. Results, in terms of susceptibility/resistance to the tested antibiotics, were always in agreement with those obtained on fresh samples (data not shown) meaning that freezing urine samples did not significantly affect the response of the MBS AST-POCT within a week. Despite the MBS AST-POCT has been conceived as near-patient testing, this result has been very important to optimize operating procedures, namely helping to exclude samples unsuitable for AST POCT analysis (e.g., evident macrohematuria) and to investigate and clarify cases in which discordant results were obtained from reference method and MBS AST POCT analysis [