North American Veterinary Licensing Examination (NAVLE) Practice Test

The most helpful laboratory test to confirm a diagnosis of rhabdomyolysis in horses is creatine kinase (CK). Rhabdomyolysis involves the breakdown of muscle tissue, which releases various intracellular components into the bloodstream, including CK. This enzyme is predominantly found in skeletal muscles, and elevated levels of CK indicate muscle damage, making it a key marker for diagnosing conditions like rhabdomyolysis.

In cases of rhabdomyolysis, a significant elevation in CK levels can be observed, often many times higher than the normal range. This rapid increase occurs within 6-12 hours of muscle injury, which makes CK a timely and useful test for diagnosing this condition. Additionally, CK levels can remain elevated for several days following the muscle damage, providing a window for detection and diagnosis.

Other laboratory tests mentioned, such as gamma glutamyl transferase (GGT), ionized phosphate, and sorbitol dehydrogenase (SDH), are not specific indicators of muscle damage. GGT primarily indicates liver function and is more relevant for assessing liver diseases. Ionized phosphate can be altered in various metabolic disorders, but it does not specifically reflect muscle damage. SDH is primarily a marker for liver injury, particularly