Objective To retrospectively analyze the results of serum beta-amyloid 42 (Aβ₄₂) tests conducted in the laboratory and explore potential issues associated with this testing.

Methods All the Aβ₄₂ test data collected up to the initiation of this study were compiled, and the positive rates for various diagnoses, including Alzheimer′s disease (AD), cognitive decline, and dementia were analyzed. Accuracy of the test kit was preliminarily validated using the kit′s own reference, mouse brain tissue, and in vitro cultured cell-based reference samples.

Results Data from 546 patients were collected, with 166 positive cases (positive rate of 30.4%). Among them, 3 out of 6 AD patients tested positive; among 149 patients diagnosed with cognitive decline and 59 dementia patients, there were 29 and 24 positive cases respectively, with positive rates of 19.5% and 40.7%. The kit′s detection of its own reference was affected by the serum matrix and failed to effectively detect positive mouse brain tissue and cellular reference samples. The kit′s detection was generally unaffected by the amyloid precursor protein (APP) of Aβ, but it did not demonstrate good recovery rates for its own reference samples added to various clinical serum specimens.

Conclusion The positive rate of serum Aβ₄₂ test results in laboratory is lower than expected, and the accuracy of the test kit may require further improvement.