Biomarkers (a shortened term for biological markers) are measurable characteristics of a certain biological condition or response to a medical or environmental exposure.

Some biomarkers, such as blood pressure or body weight, come from routine measurements taken at a doctor’s visit. Others may be found in blood, urine, or body tissues. Biomarkers can also be found at the molecular level in genes and proteins.

Doctors use biomarkers to assess a person’s health, diagnose and monitor disease progression, and determine how a person’s body is responding to treatment.

Scientists and researchers also use biomarkers to better understand the body’s biological processes, particularly in relation to health conditions or environmental toxins, and to assist with drug development.

There are seven different classifications of biomarkers:

  1. Susceptibility/risk biomarkers. These can predict a person’s risk of developing a disease. For example, a genetic test that identifies mutations in the BRCA1 and BRCA2 genes can identify a person’s increased risk for breast and ovarian cancers.
  2. Diagnostic biomarkers. These can detect or confirm a disease or medical condition (such as high cholesterol levels or proteins in urine that might indicate kidney disease).
  3. Prognostic biomarkers. These can predict the likelihood of disease progression or recurrence.
  4. Monitor biomarkers. These are used to assess the status of a disease or to quantify the body’s exposure and response to a medication or environmental agent.
  5. Predictive biomarkers. These can help predict people who are more likely than others to respond favorably or unfavorably to a medical treatment or environmental agent. For example, the presence of the HER2 protein in a person with breast cancer indicates that the person would respond well to a targeted therapy.
  6. Pharmacodynamic response biomarkers. These show that a biological response has occurred in a person who has been exposed to a medication or environmental agent. An example would be the measurement of a tumor size in response to chemotherapy. They’re often used in treatment evaluation.
  7. Safety biomarkers indicate the presence or amount of toxicity after exposure to a medical treatment or environmental agent. For example, creatine clearance biomarkers measure kidney function (to monitor kidney toxicity) after antibiotics or chemotherapy.

Biomarkers are important because they can provide a lot of information about your health. Doctors can use them to:

  • help detect early stage cancer and other diseases
  • diagnose health conditions and predict how far they have progressed
  • predict how your body might respond to certain treatments
  • monitor the likelihood of disease recurrence after treatment

Researchers are currently investigating biomarkers for the detection and treatment of mental health disorders. It’s hoped that new mental health therapies might target individual mental health conditions, unlike one-size-fits-all treatments.