Scientists might one day be able to identify people in the early stages of Alzheimer’s through their cerebrospinal fluid.

Abnormal levels of molecules in the fluid — b-amyloid, total tau and phosphorylated-tau — predicted development of Alzheimer’s with accuracy, according to a recent study by Swedish neurologists. The findings were published in Monday’s online edition of Lancet Neurology.

The study followed 180 people over four to five years. Combined molecule measurements at the start of the study identified those who developed Alzheimer’s with better than 90% accuracy.

While the Swedish study offers key information, spinal taps to collect cerebrospinal fluid are not easily done in routine medical practice, according to Dr. John Morris, a professor of neurology at Washington University School of Medicine in St. Louis. Other possible downsides to the test are the cost of the spinal tap and patient resistance to the invasive procedure.