Early Stage Testing For Kidney Disease in Cats
What is microalbuminuria?
Albumin is an important protein that is found in large quantities in the blood but is not normally present in the urine of healthy cats. The term microalbuminuria refers to the presence of very small amounts of albumin in urine ("micro" = tiny, "uria" = present in urine). Microalbuminuria may indicate underlying health problems, and is sometimes an early warning sign of primary kidney (or “renal”) disease.
What sorts of conditions result in microalbuminuria?
Many conditions can potentially lead to microalbuminuria. These include inflammatory conditions (e.g. dental disease, chronic skin disease, bowel inflammation, etc.), infectious disease (e.g. feline leukemia virus, feline immunodeficiency virus), metabolic disorders (e.g. diabetes mellitus, hyperthyroidism, etc.), hypertension (high blood pressure), and cancer.
What is the E.R.D. test for microalbuminuria and when should it be used?
The E.R.D. or Early Renal Damage test is a simple rapid test that detects microalbuminuria. It is a better test than the routine urine “dipstick” test (see article on Urinalysis) for detecting small amounts of protein in urine.
The E.R.D. test is used when the routine urine test for protein is negative and the veterinarian wants to:
- Look further for traces of protein in the urine (e.g., in a cat at high risk for kidney disease).
- Do a comprehensive health screen to detect hidden illness in a cat.
The E.R.D. should not be done when:
- A routine urine test is positive for protein. In this situation, there is clearly excess protein in the urine and an E.R.D. test will not provide any additional information. The veterinarian may suggest doing a protein-to-creatinine ratio test, which is the best test to do when larger amounts of protein are present in the urine. (See article Protein Creatinine Ratios).
- There are obvious signs of inflammation, infection, or bleeding in the urinary system. The large amount of inflammatory protein in the urine would give a falsely high reading on the E.R.D.
What sample is needed to do the E.R.D test for microalbuminuria?
All that is needed is a small amount of urine collected in a sterile container. The sample can be stored in the refrigerator for up to 24 hours, but the veterinarian may want to collect fresh urine from your cat for the test.
If my cat has microalbuminuria, does this mean my pet has serious kidney disease?
No. In fact, the majority of cats with microalbuminuria will not develop kidney disease.
"In most cases, treatment or management of the underlying health problem will make
the microalbuminuria disappear."
In most cases, treatment or management of the underlying health problem will make the microalbuminuria disappear. It is only for a small percentage of cats that microalbuminuria is truly a warning sign of early kidney disease. These cats may go on to develop serious kidney disease and possibly kidney failure. Although a complete cure may not be possible, specific steps, such as a prescription diet and medication, can be taken to slow down the progression of the disease.
If my cat has microalbuminuria, what is the next step?
If microalbuminuria is detected, your veterinarian will likely recommend further testing to look for hidden disease. The choice of tests may vary but could include basic blood tests and urinalysis (See articles on Complete Blood Count, Serum Biochemistry, and Urinalysis). If there is no evidence of underlying illness, then regular check-ups every 3-6 months including E.R.D. testing may be recommended to monitor the pet's health status and to watch any change in microalbuminuria.