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Equine Health Resource

CK & LDH Tests for Muscle Problems



These laboratory tests are commonly used to make a definitive diagnosis of rhabdomyolysis (muscle tissue damage), also known as “tying up.”

Creatine kinase (CK), and lactate dehydrogenase (LDH) are normal muscle enzymes that are released in excessive amounts when muscle cells are damaged. The amount of elevation is indicative of the number of muscle cells damaged. CK is usually the first to rise and the first to fall. LDH peaks more slowly and stays in the blood longer.

Blood is collected and tested in the laboratory for these enzymes. In most cases, this test is quickly performed in the clinic.


Monitoring both of these enzyme values over a period of time helps vets understand more about the timing and nature of muscle problems and the effectiveness of treatment. They are sensitive indicators of muscle damage.

This test may be repeated throughout a treatment course to determine the efficacy of treatment or the progression of the disease


The levels of these enzymes say nothing about the cause of the injury, they are only indicative of muscle cell damage.

If this test cannot be performed in-clinic, there will be a time delay due to offsite processing.

Horses can have muscle soreness without damaging the muscle cells and releasing these enzymes, so horses can be in muscle pain without having elevations in these enzymes.

Author: Doug Thal DVM Dipl. ABVP


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