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How Reliable is Ultrasound in PKD Diagnosis?

Posted on February 27, 2013 at 9:10 PM

PKD is polycystic kidney disease. This is a genetic disease where cysts form on the kidneys, eventually producing loss of effective renal (kidney) function. Cats diagnosed with PKD can live many years, or die quickly.

For many years feline PKD was believed to be a disease of Persian cats and cat breeds such as Ragdoll, Himalyan, Neva and other purebreeds created from Persians. Breeders with other breeds were not worried about PKD - it was a disease rarely seen.

Then the gene testing for one version of  the Persian PKD gene (PKD 1) was developed. The testing was inexpensive compared to diagnostic sonographing by a Board Certified Veterinary Internist, and breeders jumped at the chance to have the genetic testing conducted.

It was poorly understood that the PKD 1 test *only* indicated whether or not a cat had ONE of the several Persian forms of PKD. Testing negative for this PKD 1 gene mutation - even for Persians and Persian X's - only meant the feline was not effected by that *single* PKD genetic mutation. It was not diagnostic.

Unfortunately, many catteries tested genetically (@40 USD per gene test, compared to 450 - 650 USD for a echosonograph), and began declaring they were PKD free catteries...

The only predictive and accurate test for PKD in cats is via echosonograph conducted by an Board Certified Veterinary Internist with high resolution equipment.  How accurate is such testing? The Journal of Feline Medicine and Surgery found in a 2009 research study (abstract below), that the results from testing peformed as above are 100% repeatable. That's pretty definitive!!

Evaluation of the repeatability of ultrasound scanning for detection of feline polycystic kidney disease.

Wills SJ, Barrett EL, Barr FJ, Bradley KJ, Helps CR, Cannon MJ, Gruffydd-Jones TJ.SourceSchool of Clinical Veterinary Science, University of Bristol, Langford House, Langford, Bristol, BS40 5DU, UK.


Polycystic kidney disease (PKD) is the most prevalent inherited genetic disease in cats with Persian and Persian-related breeds predominantly affected. Diagnosis of PKD relied on ultrasound scanning until the recent development of the PKD gene test.

However, gene testing has limitations as it will only identify the autosomal dominant form of PKD (PKD1 - Persian PKD) and not other forms of cystic kidney disease.

Ultrasound scanning also has the advantage of being able to assess the severity and progression of disease in PKD affected cats. The aim of this study was to demonstrate the repeatability of ultrasound scanning in the detection of PKD and to assess progression of the disease over time.

This study demonstrated 100% repeatability of ultrasound scanning in the detection of PKD and has also demonstrated progression of disease in 75% of PKD positive cats assessed over a 1-year period.

J Feline Med Surg. 2009 Dec;11(12):993-6. doi: 10.1016/j.jfms.2009.07.002. Epub 2009 Aug 5.


Categories: Health & Disease, Genetics, Problem Solving