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.