Do cerebrospinal fluid transfer methods affect measured amyloid β42, total tau, and phosphorylated tau in clinical practice?

INTRODUCTION: Cerebrospinal fluid (CSF) neurodegenerative markers are measured clinically to support a diagnosis of Alzheimer's disease. Several preanalytical factors may alter the CSF concentrations of amyloid β 1-42 (Aβ1-42) in particular with the potential to influence diagnosis. We aimed to determine whether routine handling of samples alters measured biomarker concentration compared with that of prompt delivery to the laboratory. METHODS: Forty individuals with suspected neurodegenerative diseases underwent diagnostic lumbar punctures using a standardized technique. A sample of each patient's CSF was sent to the laboratory by four different delivery methods: (1) by courier at room temperature; (2) by courier, on ice; (3) using standard hospital portering; and (4) after quarantining for >24 hours. Aβ1-42, total tau (t-tau), and phosphorylated tau (p-tau) levels measured using standard enzyme-linked immunosorbent assay techniques were compared between transfer methods. RESULTS: There were no significant differences in Aβ1-42, t-tau, or p-tau concentrations measured in samples transported via the different delivery methods despite significant differences in time taken to deliver samples. DISCUSSION: When CSF is collected in appropriate tubes, transferred at room temperature, and processed within 24 hours, neurodegenerative markers can be reliably determined.