Last year a team of researchers from Rensselaer Polytechnic Institute published an impressive study suggesting it had isolated a reliable set of blood biomarkers that could successfully, and objectively, diagnose Autism Spectrum Disorder (ASD) in children. Now a follow-up study has verified those results pointing towards further clinical trials and potentially a commercially available test.

ASD is inarguably a complex and still quite mysterious neurological condition. The current diagnostic process involves close clinical assessment of behavioral patterns, meaning it is often quite difficult to clearly identify autistic children until at least the age of four. However, the earlier a diagnosis can be the made the more effective intervention treatment can be, so scientists around the world are currently working hard to find better ways to clearly identify ASD at younger ages.

A huge array of possible diagnostic tools are currently on the horizon. Some researchers are studying EEG and MRI results to identify early signs of ASD, while others are looking at behavioral characteristics such as irregular crying patterns or eye-gaze tracking. Perhaps the most controversial area of diagnostic research in the field is examining objective biomarkers to identify the condition.

From blood and urine, to saliva, researchers are hunting for something unique that can signal the presence of ASD in young infants. The big challenge is that as the neurological mechanism behind ASD is still fundamentally unclear, any biomarker identified with higher rates of autism found may ultimately be coincidental, and there are dangers in misdiagnosing the condition.

The research from the Rensselaer Polytechnic Institute doesn't entirely overcome these concerns, but it does present the most comprehensive ASD biomarker proposal to date. This research proposes a collection of 24 different metabolites can be algorithmically studied to determine whether a subject has ASD. Last year's initial research reported a remarkable 97.6 percent success rate in identifying ASD subjects and a 96.1 percent success rate in identifying healthy subjects.

This new study into the efficacy of the test doesn't engage an independent clinical trial. Instead the researchers have gathered appropriate biometric data collected from other trials. The new data came from ASD studies at the Arkansas Children's Hospital Research Institute. Data from 154 subjects was effectively collected, but due to the nature of what was previously analyzed in the appropriated studies, only 22 of the 24 metabolites could be included in this new review.

The results were again, impressively accurate, although this time only 88 percent of subjects were correctly diagnosed. The researchers suggest that the two missing metabolites in this new review explain the drop in accuracy from their earlier results.

Though the specificity of the biomarker test is certainly impressive, this research should be approached with caution. These targeted metabolites have not been connected to ASD in any mechanistic way so a great deal more research needs to be done to ensure they do not correlate with other behavioral disorders.

Another major limitation to the study is that this latest dataset comprised blood from children between three and ten years of age. For this diagnostic test to be of any predictive use the cohort studied will need to be much younger so as to clarify that these metabolites do correspond with ASD in early-infant stages.

This is undoubtably a successful step towards a vitally important diagnostic blood test for autism, but we may be several years away from safely, and confidently, implementing a test like this into hospitals and clinics.

The new research was published in the journal Bioengineering and Translational Medicine.