Two-step test improves accuracy of Alzheimer’s disease screening.

Two-step test improves accuracy of Alzheimer's disease screening.

A Breakthrough in Alzheimer’s Testing: Improving Accuracy and Reducing Invasive Procedures

Diagnostic Strategy for Alzheimer’s

Alzheimer’s disease, a neurodegenerative condition that causes memory impairment, has been the focus of a groundbreaking study conducted by Swedish researchers. They have designed a two-step disease detection process that may revolutionize testing for Alzheimer’s, reducing unnecessary invasive procedures and improving diagnostic accuracy. This innovative approach has the potential to not only enhance patient care but also reduce healthcare system costs.

According to the Alzheimer’s Association, Alzheimer’s affects approximately 10% of people over the age of 65 in the United States, making it crucial to detect the disease early and initiate interventions to slow its progression. Currently, one test available for aiding the diagnostic process is the p-tau217 biomarker blood screen, which checks for a buildup of the amyloid protein that can cause organ damage.

However, one of the drawbacks of the current p-tau217 screening is the occurrence of a high number of false negatives or positives, leading to unnecessary invasive testing. To address this issue, the Swedish researchers collaborated with Canadian researchers to find a way to improve the accuracy of diagnostic results.

Their two-step diagnostic process begins by combining p-tau217 testing with other risk factors in individuals with mild cognitive impairment. This step helps determine their risk of developing Alzheimer’s disease. For individuals with an uncertain risk outcome, the researchers then perform a cerebrospinal fluid biomarker test, resulting in an improvement in the detection of false negatives or positives.

The study analyzed data collected from 348 participants with mild cognitive impairment, obtained through the BioFINDER studies on memory. The participants had to meet specific criteria, including medical referral for memory issues, no dementia diagnosis, and a mini-mental state examination (MMSE) score of 24–30 points. Those with substance abuse, refusal of neuropsychological testing, or neurological issues unrelated to Alzheimer’s were excluded.

The researchers focused on participants who had information available about the plasma p-tau217 biomarker, cerebrospinal fluid testing, and APOE e4 data (genetic risk information for Alzheimer’s diagnosis). By utilizing age and biomarker data, they assessed the risk of amyloid PET positivity in patients with mild cognitive impairment, indicating an increased risk for Alzheimer’s.

Next, the researchers placed the participants into low, intermediate, or high-risk groups and tested the sensitivity levels of these groups. In the second step, they checked the CSF Ab42/40 ratio of people in the intermediate-risk group, as their risk was more uncertain. This targeted approach aimed to improve the diagnostic model and reduce inaccurate diagnoses.

The results of the study demonstrated that by using different threshold sensitivities, the accuracy for amyloid PET positivity ranged from 88.2% to 92.0%. Importantly, the number of cerebrospinal fluid tests needed decreased by up to 85.9%. This significant reduction indicates that the two-step workflow may significantly reduce the need for invasive testing while maintaining high overall classification accuracy.

The screening process proved highly accurate in identifying individuals at high risk of developing Alzheimer’s disease. If further research confirms the efficacy of this method, unnecessary invasive tests on individuals already at high risk for the disease could be significantly reduced. By focusing resources on the intermediate-risk group, the study showcases the benefits of targeted allocation.

While the findings of this study are promising, it is important to consider the potential conflicts of interest among the authors. Several researchers declared receiving funding and speaking fees from various pharmaceutical companies, which may cloud the objectivity of the study’s conclusions. Dr. Clifford Segil, a neurologist not involved in the research, highlighted this concern, stating that the diagnosis of dementia requires a neurologist’s expertise and cannot be solely based on blood tests or brain scans.

Dr. David Merrill, a geriatric psychiatrist, noted that a test like this could be valuable as it is less invasive than current testing methods involving cerebrospinal fluid or PET scans. He emphasized the advantages of a simple blood test, including wider dissemination, minimal risk, and lower costs.

In conclusion, the two-step disease detection process developed by Swedish researchers represents a significant breakthrough in Alzheimer’s testing. Its potential to improve accuracy and reduce the need for invasive procedures brings hope for earlier detection and interventions. However, further studies are required to validate this approach and ensure its effectiveness.