Early Renal Disease (ERD) - The Detection of Microalbuminuria in Cats and Dogs

What is microalbuminuria?

Albumin is an important protein found in the bloodstream. It is not normally present in the urine of healthy dogs and cats. Microalbuminuria refers to the presence of small quantities of albumin in the urine. Until recently conventional renal diagnostic methods could only detect "end stage" renal disease, when approximately 75% of functional kidney tissue (nephrons) had been destroyed.

Recently, technology has allowed the development of more sensitive tests so that minute quantities of albumin can be detected in the urine. This can, in some cases, act as an early warning system for possible future kidney problems.

What are the problems that can result in microalbuminuria?

Many conditions can lead to damage of the nephrons which are the microscopic kidney filtration units (nephrons) resulting in the appearance of minute quantities of albumin in the urine. These include inflammatory conditions such as dental disease, chronic skin disease and bowel disease as well as infectious diseases, e.g. feline leukaemia virus, Ehrlichia infection, heartworm and Lyme disease. Metabolic problems such as diabetes, hyperthyroidism, hypertension and certain cancers can also be responsible.

Is the ERD test complicated?

The test is based upon enzyme-linked immunosorbent assay (ELISA) technology. As a result, the test is relatively simple and can often be carried out at the practice.

All that is needed is a small quantity of fresh urine.

If the test is positive does this mean my pet has progressive renal disease?

No, not necessarily. A positive result is merely an early warning sign. In the majority of cases management of the underlying health problem results in resolution of the microalbuminuria. In some cats and dogs, however, the problem persists and the degree of microalbuminurea increases over time. These animals are at risk and should be regularly monitored. 

If the test is positive, what is the procedure?

We will discuss this with you fully. Depending on the results further testing may be necessary to assess the underlying problem. Alternatively we may recommend regular check-ups every three to six months carrying out further ERD testing to check if the problem is worsening. If so, underlying kidney disease is likely to be present and, although a complete cure is unlikely, early detection at least means that supportive treatment may be commenced and the progression of the disease may be decreased.