What are pain biomarkers and why are they useful to us? Pain biomarkers are useful and measurable indicators that can be used to identify or quantify pain in individuals. There are currently no pain biomarkers approved by the FDA for use in drug trails, so identifying reliable biomarkers is a goal of many pain studies. In general, the best way to identify pain under most circumstances is to ask the patient. However, not everyone is able to report their pain — for example, babies, anaesthetized or comatose patients, and demented patients are all unable to give reliable ratings of their pain. Although animals show pain behaviors, they likely experience aversive stimuli different from humans. Thus, it is unlikely that direct comparisons of animal and human pain will be ever be possible.