Authors (including presenting author) :
Shea YF(1), Wong YL(2), Yam KK(1), Wong FCK(2), Wong TK(1), Chan KPF(1), Cheung YWE(3), Mak HKF(3), Ip SMM(1), Chan WC(4), Chan KH(1), Chiu PKC(1), Lam CW (2)(5)
Affiliation :
(1)Department of Medicine, Queen Mary Hospital, Li Ka Shing Faculty of Medicine, University of Hong Kong, (2)Division of Chemical Pathology, Department of Pathology, Queen Mary Hospital, (3)Department of Diagnostic Radiology, Queen Mary Hospital, Li Ka Shing Faculty of Medicine, University of Hong Kong, (4)Department of Psychiatry, Li Ka Shing Faculty of Medicine, University of Hong Kong,(5)Department of Pathology, Li Ka Shing Faculty of Medicine, University of Hong Kong
Introduction :
Plasma phosphorylated tau (P-tau) 217 has been demonstrated to be a useful blood biomarker for detecting Alzheimer’s disease (AD) pathology. It has not been studied in the Chinese population in real world memory clinic.
Objectives :
The primary objective of this study was to determine the local cut-off of plasma P-tau 217 using S-PLEX® for the local Chinese population. It was hypothesized that S-PLEX® plasma P-tau 217 has similar discriminative power in the Chinese. The secondary objective was to apply the determined cut-off in a similar cohort of patients in our memory clinic in order to study the overall change in diagnoses in a real-world setting. The relationship between plasma P-tau 217 and behavioral and psychological symptoms (BPSD) of dementia as measured by Neuropsychiatric Inventory scores (NPI) were explored.
Methodology :
Ninety-eight patients were recruited consecutively between 1st March, 2024 and 19th July, 2024 from Memory Clinic of Queen Mary Hospital. These patients were offered measurement of plasma P-tau 217 using the S-PLEX®. Validation cohort consisted of 48 patients with amyloid positron emission tomography (PET) and they were utilized to determine the cut-off of plasma P-tau 217 using the receiver operating curve analysis. The cut-off of S-PLEX® was subsequently applied to the application cohort (n=50) without amyloid PET to study the clinical impact.
Result & Outcome :
Using the single cut-off plasma P-tau 217 >10.08 pg/ml, the sensitivity and specificity of the test was 86.67% and 88.89% respectively (area under the curve = 0.94). After applying the determined cut-off in the application cohort, 50% (19/38) of the clinically diagnosed AD patients were diagnosed as non-AD and 16.7% (2/12) of the clinically diagnosed non-AD patients were classified as AD. Plasma P-tau 217 correlates with Neuropsychiatric Inventory Scores (correlation coefficient 0.42, 95% CI 0.12-0.65, p=0.01) in the whole cohort of plasma P-tau 217 defined AD patients. Plasma P-tau 217 is useful in diagnosing AD in the Chinese population in memory clinic with diverse underlying etiologies of cognitive impairment.
