First HK consensus statement on use of Alzheimer’s disease biomarkers and anti-amyloid therapies

In response to increasing need for accurate diagnosis of Alzheimer’s disease (AD) pathology with the availability of anti-amyloid therapies (AATs), a 20-member expert panel in Hong Kong has formulated the first multispecialty consensus recommendations to provide practical locally-tailored guidance for healthcare practitioners on the use of imaging and biomarkers for AD diagnosis and AATs.

The expert panel comprised 20 multidisciplinary specialists from five professional societies (representing geriatrics, neurology, psychiatry/dementia research, nuclear medicine, and diagnostic radiology specialties). They reviewed and used a modified Delphi process to finalize 26 statements spanning diagnostic indications, choice and interpretation of biomarkers, as well as AAT use guidance, based on current evidence and expert opinion. [Hong Kong Med J 2026;doi.org/10.12809/hkmj2514198]

Panellists evaluated and voted on each statement on a 9-point Likert scale (1 = strongly agree; 2 = agree; 3 = moderately agree; 4 = mildly agree; 5 = neutral; 6 = mildly disagree; 7 = moderately disagree; 8 = disagree; 9 = strongly disagree). A statement was considered “accepted” if at least 75 percent of panellists rated it 1–3, and “rejected” if at least 75 percent rated it 7–9. All 26 statements met the “accepted” threshold, and none of the statements had votes in the 6–9 range.

Statements with levels 1 & 2 agreement votes forming 100 percent consensus  

Clinical use of biomarkers

·       Biomarkers may be used in individuals with young-onset dementia (ie, onset before 65 years of age).

·       Biomarkers may be used in individuals with suspected AD and an atypical clinical course (eg, non-amnestic presentation, rapid or slow progression, or mixed aetiology).

·       Biomarkers may be used in individuals with suspected AD and an amnestic presentation.

·       Amyloid PET scanning (using visual interpretation, with or without assistance from standardized uptake value ratio or the Centiloid scale) can be used to confirm AD pathology.

·       Tau PET may aid in the diagnosis of atypical AD and may provide prognostic information in individuals with mild cognitive impairment or those receiving AAT. At present, it should not be used routinely.

·       Cerebrospinal fluid biomarkers (Aβ42, total tau, phosphorylated tau 181, and ratios including Aβ42/Aβ40, total tau/Aβ42, and phosphorylated tau 181/Aβ42) may be used to confirm AD pathology.

AAT use

·       Patients unable to undergo regular MRI (eg, due to claustrophobia or presence of MRI-incompatible devices) should not receive AAT.

·       Serial MRI scans (at least 1.5 T, preferably 3.0 T) using a standardized protocol and consistent magnetic field strength are recommended during AAT to monitor the development of amyloid-related imaging abnormalities (ARIA).

·       Apolipoprotein E genotyping is recommended before initiation of AAT.

·       Infusion reactions, including hypersensitivity and acute symptoms such as fever, chills, or nausea, may occur during administration of AAT. Protocols should be developed to manage various infusion reactions so that medical staff in wards or day centres can respond promptly and reduce the risk of recurrence.

Statements with levels 1 & 2 agreement votes forming 95 percent consensus:  

Clinical use of biomarkers

·       Biomarkers can be used when AAT is under consideration.

·       The Centiloid scale is encouraged for comparison of amyloid PET scans performed across different centres and for longitudinal monitoring of response to AAT.

·       AD plasma biomarkers may be considered as an initial test before proceeding to amyloid PET scanning for confirmation.

·       Plasma phosphorylated tau 217 can be used to support the diagnosis of AD pathology. A three-range (two-cutoff) approach, with test sensitivity and specificity of at least 90 percent in the intended population, is recommended.

·       Given the rapid progress in the field of AD biomarkers, local professional bodies should organize updates and share local experience regarding their use.

AAT use

·       The use of AAT should be reviewed if patients progress to moderate dementia.

·       Blood pressure should be adequately controlled according to age and comorbidities before initiation of AAT.

·       Patients and their relatives should be fully informed of the common non-specific symptoms of ARIA, including headache, dizziness, confusion, nausea, vision changes, gait disturbance, or seizures. They should be advised to inform the attending physician or emergency department promptly if such symptoms occur, and brain MRI should be arranged as early as possible (if indicated).

·       Patients receiving AAT should have an alert in their electronic medical record or be issued a drug card.

·       A multidisciplinary approach is recommended when administering AAT. This approach involves clinicians experienced in the management of cognitive impairment (eg, geriatricians, neurologists, psychiatrists, nuclear medicine physicians, and radiologists).

Summary and future directions

“Amyloid PET and CSF biomarkers remain the surrogate gold standards in the diagnosis of AD, while other biomarkers that achieve a minimum sensitivity and specificity of at least 90 percent in the intended population may also be used,” the authors summarized. “For the administration of AAT, clinicians should be aware of contraindications, and relevant risks should be explained to patients and their caregivers.”