Repeatability of the Oral Sugar Test (OST) in Horses

Status: Not currently enrolling


The oral sugar test (OST) has been developed as a new test for diagnosing the glucose and insulin problems involved in the development of laminitis (founder) in horses.  This new test is easily performed and provides more information than just a single blood sample.  However, we do not know enough about the consistency of results, so this study is being conducted to compare results of two tests performed 7 to 14 days apart.

The OST involves fasting your horse and then collecting 3 blood samples (20 mL each) from the jugular vein using a needle before and 60 and 90 minutes after giving corn syrup (0.15 ml/kg) by mouth.  Our fasting procedure is as follows:

  •         For an OST beginning between 8:00 and 10:00 AM, we ask you to bring your horse into a dirt paddock or stall and leave only one flake of hay at 10 PM the night before.
  •         For an OST beginning between 4:00 and 6:00 PM, we ask you to bring your horse into a dirt paddock or stall and leave only one flake of hay at 6:00 AM the same morning.

Inclusion Criteria:

Horses with suspected or confirmed glucose and insulin problems associated with equine metabolic syndrome (EMS) or Cushing’s disease (also called pituitary pars intermedia dysfunction).

Horse owners must allow their horse to be tested twice 7-14 days apart.

Exclusion Criteria:

Horses that are currently suffering from other diseases.  For example, any medical problem causing fever.

Blood samples must be collected without causing significant stress, so horses with a fear of needles are excluded.

Client Benefits:

This study covers the cost of measuring glucose and insulin in the blood samples collected, but horse owners are financially responsible for costs associated with two veterinarian visits to farm and professional time for performing the tests.

Contact Information:

Diane Welsh, Clinical Trial Technician                                                               ‘