Andrea L Benedet, Burak Arslan, Kubra Tan, Hanna Huber, Ilaria Pola, Guglielmo Di Molfetta, Hlin Kvartsberg, Anna Orduña Dolado, Shorena Janelidze, Kaj Blennow, Henrik Zetterberg, Oskar Hansson, Pedro Rosa-Neto, Nicholas J Ashton. Diagnostic Value of Serum p-tau217 in Alzheimer Disease: Equal to Plasma in Levels and Clinical Utility? Clinical Chemistry, Volume 72, Issue 2, February 2026, Pages 303–315, https://doi.org/10.1093/clinchem/hvaf162

Diagnostic Value of Serum p-tau217 in Alzheimer Disease: Equal to Plasma in Levels and Clinical Utility?

Clinical Chemistry Podcast

# Full Transcript

**Podcast:** Clinical Chemistry Podcast

## Transcript

This is a podcast from Clinical Chemistry, a production of the Association for Diagnostics and Laboratory Medicine. I'm Bob Barrett. Alzheimer's disease is the leading cause of dementia and current estimates predict a dramatic surge in new cases with an estimated 80 million affected individuals worldwide by 2030. The last few years have brought tremendous therapeutic advances highlighted by the recent approval of monoclonal antibody treatments that can slow the rate of disease progression.

However, accurate diagnosis remains a challenge, with misdiagnosis rates of 30% in specialized clinics and substantially higher rates in the primary care environment. Clearly, there is a need for improved diagnostic tools, and substantial work is focused on blood-based biomarkers to differentiate between affected and unaffected individuals. In a curious twist, most of the work to date is focused on plasma, but many hospital systems prefer serum.

This raises the question, are there substantial differences in Alzheimer markers in serum versus plasma? And if so, can decision thresholds established using plasma be safely transferred to serum samples? A new research article in the February 2026 issue of Clinical Chemistry tackles this question by measuring p-tau217 impaired serum and plasma samples from patients across the spectrum of Alzheimer's symptoms. Today, we'll speak with one of the article's lead authors.

Dr. Barack Arslan is working at the Clinical Neurochemistry Laboratory at the Sahlgrenska University Hospital in Gothenburg, Sweden. His work focuses on the validation and clinical implementation of fluid biomarkers for neurodegenerative disorders, with a particular emphasis on Alzheimer's disease. Dr. Arslan, let's get to the basics first. Could you tell us a bit more about fluid biomarkers in Alzheimer's disease? Why do we need blood-based biomarkers, and which ones are the most promising?

Yes, of course. Alzheimer's disease is a chronic neurodegenerative disease and the most common cause of dementia. And it is characterized by two key pathological features. First, extracellular amyloid plabs and intracellular neurofibrillary tangles composed of hyperphosphoridated tau. For over a century, definitive diagnosis has relied on only neuropathological confirmation of these changes.

Today, however, we have some tools that can detect Alzheimer's pathology in living individuals. This is done using imaging techniques such as amyloid and tau pads, as well as well-established cerebrospinal fluid biomarkers, including the amyloid beta-42-40 ratio, phosphoridated tau, and total tau.

And we know that CSF biomarkers have become increasingly standardized and were introduced into clinical practice after 2020 with regular approvals and the development of certified reference materials for these biomarkers. These tools are now routinely used in specialized clinical laboratories to support clini...

Diagnostic Value of Serum p-tau217 in Alzheimer Disease: Equal to Plasma in Levels and Clinical Utility?

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Diagnostic Value of Serum p-tau217 in Alzheimer Disease: Equal to Plasma in Levels and Clinical Utility?

Transcript

Built for investment professionals

Every day you wait, your competitors are findingedge in conversations you're not hearing.

Every day you wait, your competitors are finding
edge in conversations you're not hearing.