The push for earlier detection of Alzheimer’s disease has encouraged researchers to continue searching for signs of the disorder in seemingly healthy individuals. One culprit behind the disorder may be tau protein, which, when defective, destabilizes cellular microtubules, forming tangles that might disrupt neuron function. Now, a study appearing in the Archives of Neurology adds to the argument that tau protein could eventually have diagnostic potential.

Geert De Meyer of Ghent University in Belgium and his colleages found a biological signature comprised of distinctive levels of three markers present in cerebrospinal fluid — beta-amyloid protein 1-42, total tau protein and phosphorylated tau181P— that they link to Alzheimer’s disease.

The study examined more than 400 patients: 114 healthy adults, 200 with mild cognitive impairment and 102 with Alzheimer’s dementia. The three biomarkers were found in 90% of Alzheimer’s patients, and 72% of those with mild cognitive inhibition. However, it was also found in 36% of cognitively normal patients, meaning that it’s still not an ideal detection system.

Another study appearing in the Archives of Neurology followed 880 healthy individuals for more than four years, of whom 70 developed Alzheimer’s disease. Stephanie Cosentino of Columbia University Medical Center in New York and her colleagues found that higher plasma levels of beta-amyloid protein fragments “were associated with faster cognitive decline, primarily in memory.”

The new diagnostic tests, though far from ready for primetime, come on the heels of last month’s headline-grabbing meeting of the Alzheimer’s Association in Honolulu, Hawaii. At the annual meeting experts proposed retooling the criteria for diagnosing Alzheimer’s. Under the new guidelines, Alzheimer’s would be divided into three stages: pre-clinical disease, mild cognitive impairment and full-blown dementia. Doctors would be encouraged to pinpoint the early signs of Alzheimer’s using brain scans, MRIs, and spinal taps.

But rolling out inferior diagnostic tools for Alzheimer’s could cause confusion in the clinic. Some argue that without reliable biomarkers for Alzheimer’s, we could be at risk of over-diagnosing the disorder.