Serum Bile Acid Database

The purpose of the OFA serum bile database is to provide a phenotypic screening tool for liver shunts (PSVA – portosystemic vascular anomaly) and MVD (microvascular dysplasia).  The two conditions are believed to be both related and congenital.  Normal bile acid levels provide a sensitive test to indicate the absence of either of these inherited conditions, giving breeders valuable information in making informed breeding decisions.

Bile acids are compounds that are made in the liver, stored in the gall bladder and help with the digestion of foods.  During digestion, the gall bladder contracts and pushes the bile acids into the small intestine where they mix with the foods and break down fats into smaller particles for easier absorption.  When digestion is finished, the bile acids are absorbed by the intestine, passed into the blood stream, and returned to the gall bladder where they are stored for the next meal.

Elevated bile acids indicate there is a problem with the liver, but do not provide specific diagnostic information regarding cause, severity, or reversibility of the problem.  Dogs with elevated bile acids should be monitored at a minimum, and may require additional diagnostic testing such as an ultrasound or liver biopsy to determine an appropriate course of action.

For the purposes of the OFA serum bile acid database, test results are accepted from IDEXX, Antech, or veterinary college diagnostic laboratories.  This is to ensure evaluation against consistent reference ranges.  Test results processed within veterinary clinics will not be accepted.  For inclusion in the OFA serum bile acid database, the dog must be a minimum of 16 weeks of age at the time of the testing.

For this test, labs measure the amount of bile acids in the blood serum.  It is common for a paired test (pre-prandial and post-prandial) to be done.  Pre-prandial samples are collected after a minimal period of fasting.  Post-prandial samples are collected 2 hours after a small amount of high protein food has been fed.  The OFA protocol only requires the post-prandial (2 hour) sample.  The pre-prandial (fasted) sample is optional, but it is recommended in order to establish a better baseline for comparison.

OFA Reporting:

Dogs with post-prandial (2 hour) serum bile acid values under the lab’s specific high-normal range cutoffs will be reported as Normal.

If both pre-prandial (fasted) and post-prandial (2 hour) samples were submitted for evaluation, dogs with BOTH reported serum bile acid values under the lab’s specific high-normal range cutoffs will be reported as Normal.

All other results are considered equivocal for clearance purposes.  Dogs with pre or post prandial levels outside of the normal reference range require additional testing to determine whether a liver shunt or MVD is present.

OFA Serum Bile Acid Veterinary Protocol

 (valid results require strict adherence to the following):

Optional Pre –Prandial (fasted) Collection:  Your examining vet and the laboratory may recommend a pre-prandial (fasted) sample to establish a baseline.

  • Prior to sample collection, withhold food from the dog being tested for at least 8 hours.  If collecting a pre-prandial sample, the fast is critical and must be adhered to.  This includes no treats or chew toys.
  • Collect a 3mL blood sample from a peripheral vein and place in a serum tube (red top without the serum separator plug)
  • Label the tube “FASTED”, along with the dog’s identification information
  • Allow the sample to clot for at least 15 minutes, and centrifuge no longer than 30 minutes after the blood is collected
  • Harvest the serum and place in a plastic tube suitable for transport

Mandatory Post-Prandial (2 hours after feeding) Collection:

  • Prior to sample collection, withhold food from the dog being tested for at least 8 hours.  For both pre and post prandial sample collection, the fast is critical and must be adhered to.  This includes no treats or chew toys.
  • Relative to the dog’s size, feed the dog a small portion of a high protein canned food (avoid dry kibble)
  • Wait 2 hours, and collect a 3mL blood sample from a peripheral vein and place in a serum tube (red top without the serum separator plug)
  • Label the tube “2-HOUR”, along with the dog’s identification information
  • Allow the sample to clot for at least 15 minutes, and centrifuge no longer than 30 minutes after the blood is collected
  • Harvest the serum and place in a plastic tube suitable for transport

Ship the sample(s) to the laboratory, making sure all tubes are labeled appropriately with the dog’s ID and pre- and post-prandial indication (“FASTED” and “2-HOUR).