IDEXX Reference Laboratories

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IDEXX Cystatin B Test

A first-of-its-kind veterinary test to detect kidney injury.

With the IDEXX Cystatin B Test, IDEXX’s kidney health suite is more comprehensive than ever. Never before have veterinarians been able to detect active or acute injury to the kidneys with a kidney injury marker. Now with the IDEXX Cystatin B Test, a simple, urine-based test for unwell patients, you can uncover renal tubular injury when clinical signs may or may not be apparent.

Can a kidney tell you if it’s injured? It can now.

If you don’t know an injury has occurred, how can you treat for it? The IDEXX Cystatin B Test helps uncover subclinical ongoing (active) injury to the kidney that may or may not affect its function.

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Quick start guide

The IDEXX Cystatin B Test is included in select IDEXX Reference Laboratories panels that include urine testing and are most often used for unwell patients, and it is also offered as a stand-alone or add-on test.

Here’s everything you need to start using this innovative test right away.


Cystatin B is a member of the cystatin family of cysteine proteases. It is a small intracellular protein that is released into the urine when epithelial cells are damaged or die.

Kidney disease is a pathological state or condition where the function of the kidneys has been permanently altered. A patient is diagnosed with kidney disease when the kidneys’ ability to do one or all of their primary functions is compromised. Kidney injury refers to damage to the kidneys that may or may not affect the function of the kidneys.

Cystatin B is an intracellular protein that is released into the urine following damage to renal tubular epithelial cells. Cystatin B can be used to identify kidney injury but does not evaluate kidney function. Other renal biomarkers, such as SDMA, creatinine, and BUN, correlate with glomerular filtration rate (GFR) and are used to evaluate kidney function.


Totally Tubular: Novel Markers in Kidney Injury

"Hold it!" Don't Forget the Urinalysis

Expanding the Toolbox: Cutting-Edge Diagnostics to Improve Outcomes in Patients with Renal Disease

More kidney health webinars



What is Cystatin B?


How to interpret an increased IDEXX Cystatin B Test result with other kidney diagnostics


How to interpret a normal IDEXX Cystatin B Test result with other kidney diagnostics


Differentiating active versus acute kidney injury

6 examples where the IDEXX Cystatin B Test is beneficial.

  1. You suspect a toxin exposure and are looking to confirm active injury when 
functional markers may not have changed yet.
  2. You are monitoring treatment and recovery from an active injury event.
  3. You need to know if a dog with IRIS CKD Stage 1 is progressing.
  4. You have a patient that may be at higher risk when taking NSAIDs.
  5. You’re monitoring the effect on kidneys during a shock event, such as heat stroke or acute pancreatitis.
  6. You’re assessing the impact of a hypotensive event during anesthesia to
 determine whether kidney injury is ongoing.
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Intuition confirmed.

The most comprehensive solution for kidney health.

Your view into kidney health just got clearer. IDEXX’s suite of kidney health diagnostics includes IDEXX SDMA testing for kidney function, the IDEXX FGF-23 Test for management of kidney disease, and, soon, the IDEXX Cystatin B Test for detection of kidney injury. The addition of the IDEXX Cystatin B Test provides a comprehensive view of the kidney by uncovering kidney injury with or without reduced kidney function, complementing SDMA and other functional markers. You’ve trusted our diagnostics for kidney function and management. With the IDEXX Cystatin B Test, you can trust the only diagnostic for active injury.

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Our team is here to support you how and when you need it, including personalised guidance, education, and training. Through VetConnect PLUS, easily find results, review trending and recommended next diagnostic(s).

Forms and other resources

Access IDEXX Reference Laboratories specimen guidelines, forms, articles, and more.

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Learn more about the IDEXX Cystatin B Test.

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