Immune-Mediated Hemolytic Anemia (IMHA)

English cocker spanielImmune-Mediated Hemolytic Anemia, or IMHA, is an autoimmune disease in dogs in which the body attacks its own red blood cells. This can lead to very low red blood cell counts (anemia) that require multiple blood transfusions. It can also predispose dogs to forming blood clots, mostly in the lungs or in the brain. Treatment can require extended hospitalization, drugs that suppress the immune system, and often blood thinners. Some dogs do quite well with minimal treatment, however for many others the disease is unfortunately fatal.

Dr. Steven Friedenberg and the Canine Genetics Laboratory at the University of Minnesota College of Veterinary Medicine are working to identify gene mutations responsible for the development of IMHA. We are working with collaborators at The Ohio State University, Purdue University, Cornell University, and Iowa State University. Our goal is to use this research to better understand the disease mechanism and disease triggers, and also to develop a test that can help breeders decrease the incidence of the disease. We are also interested in using the results of our research to help predict disease severity and response to treatment.


  • We are particularly interested in English Cocker Spaniels and Clumber Spaniels
  • However, any dog with a current or former diagnosis of IMHA can qualify

Requirements to participateClumber Spaniel

  • Dogs of any age that have been diagnosed with IMHA, either currently or in the past
  • Your willingness to volunteer a blood sample from your dog for genetics research

Study information for owners

Please contact Dr. Friedenberg (or have your veterinarian contact him) at if you are interested in having your dog donate a blood sample. Dr. Friedenberg will discuss with you whether your dog is a candidate for the study, and obtain the necessary medical records from either you or your dog’s veterinarian.

If your dog meets the criteria for the study, we will send your veterinarian a prepaid shipping label to send us a blood sample from your dog. You can then schedule a brief appointment with your veterinarian for a blood draw. After the visit, your veterinarian will send the blood sample to us, along with a consent form and any relevant medical records.

Please also bring a copy of your dog’s pedigree to your veterinarian if you have a copy, however this is not strictly necessary. You can also e-mail it to Dr. Friedenberg directly.

Study information for veterinarians

If you have any clients who you think would be interested in participating in our study, or if your client has approached you about this study, the following information should be helpful.

We are soliciting DNA samples from English Cocker Spaniels and other breeds that you are currently treating or have treated in the past for primary IMHA.

Inclusion and exclusion criteria for the study are as follows:

Inclusion criteria

  • CBC documenting HCT < 30%
  • Positive results on one of the following tests:
    • Slide autoagglutination test (macro or micro)
    • Pathologist-reviewed blood smear documenting spherocytosis
    • Coombs test with a titer of 1:64 or greater
    • Flow cytometry documenting erythrocyte surface-bound IgG or IgM

Exclusion criteria

  • Thoracic radiographs showing evidence of disease consistent with neoplasia (at the time of diagnosis)
  • Abdominal radiographs showing evidence of disease consistent with neoplasia or a foreign metallic object (at the time of diagnosis)
  • Abdominal ultrasound showing evidence of systemic disease at the time of diagnosis
  • Evidence of true infection with any erythrocyte-borne pathogen or rickettsial disease based upon blood smear, culture, convalescent IFA, or PCR

At a minimum, patients must meet (or have met) both inclusion criteria concurrently. It is not necessary to have evaluated patients for all of the exclusion criteria. However, if you did perform any of the listed exclusion criteria tests and your patient meets one of them, unfortunately we cannot include that patient in the study.

If you have any clients meeting the above criteria who might be interested in donating a blood sample for genetics research, please e-mail Dr. Steven Friedenberg at with your contact details and we will arrange a time to discuss the case. If your patient qualifies, we will send you a prepaid shipping label to send us the sample at our expense. The study requires the following to be shipped:

  • 4-5 mL of blood in 1 or 2 EDTA/purple top tubes
  • Relevant medical records to confirm the diagnosis
  • A filled out consent form
  • A copy of the dog’s pedigree, if provided by the owner

We will provide you with further shipping details once we ensure that your patient is a good candidate for the study.


English cocker spaniel

Thank you very much for your interest in our genetic study – we genuinely appreciate your assistance with this important research!



Funding for this research is graciously provided by the English Cocker Spaniel Club of America Health & Rescue Organization, the Clumber Spaniel Health Foundation, as well as internal grants from the University of Minnesota.

About the investigator

Dr. Friedenberg is a board-certified veterinary critical care specialist and a geneticist, and is currently an Assistant Professor at the University of Minnesota College of Veterinary Medicine. He became interested in genetic diseases while working for Dr. Rory Todhunter at Cornell University as a vet student, and developed a particular interest in autoimmune diseases during his residency training at The Ohio State University. He holds a PhD in genetics from North Carolina State University, and is very interested in computational biology and its applications to finding better ways to diagnose, prevent, and treat genetic disorders.

Canine Genetics Lab Home & Contact Info

Canine Genetics Lab Home & Contact Info


Canine Genetics Lab
University of Minnesota
1988 Fitch Ave
AS/VM 295
St. Paul, MN 55108


Submission Form and Protocol

Submission Form and Protocol

Please contact Dr. Friedenberg (or have your veterinarian contact him) at if you are interested in having your dog donate a blood sample.