Investigations
1st investigations to order
serum creatine kinase (CK) level
Test
This is the most specific test for diagnosis of rhabdomyolysis.[1]
Levels have been shown to correlate with severity.
Result
increased to >5 times normal, or >1000 IU/L
serum electrolytes
Result
elevated potassium, magnesium, and phosphate; low calcium
renal function
Test
Baseline obtained and determinations followed up.
Used to guide treatment and course.
Result
elevated urea and creatinine
liver function
Test
Baseline obtained and determinations followed up.
Result
elevated aspartate aminotransferase and alanine aminotransferase
FBC
Test
Taken as baseline and monitored for the development of disseminated intravascular coagulation.
Result
decreased haemoglobin and platelet count
coagulation studies
Test
Taken as baseline and monitored for the development of disseminated intravascular coagulation.
Result
elevated prothrombin time, activated PTT, and INR
urine dipstick
Test
Only found in 50% of patients.
Result
positive for blood
urine microscopy
Test
Patients with positive blood on urine dipstick, but negative red blood cells (RBCs), should have CK tested.
Result
negative for RBCs
Investigations to consider
muscle biopsy
Test
Only of value if genetic aetiology is suspected.
Result
myonecrosis
thyroid-stimulating hormone
Test
To evaluate for hypothyroidism.
Result
increased
erythrocyte sedimentation rate
Test
To screen for inflammatory myopathies.
Result
elevated
antinuclear antibodies
Test
To evaluate for autoimmune causes.
Result
positive
toxicology screen
Test
To evaluate for illicit drug, opiate, or alcohol use.
Result
positive screen
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