Diagnostic Tests for Rhabdomyolysis

Core Laboratory Tests

Serum myoglobin is released from damaged muscle tissue and can be detected earlier than creatine kinase (CK), though it has a shorter half-life, in patients with suspected rhabdomyolysis 1
A complete electrolyte panel is essential to assess for hyperkalemia, hypocalcemia, and hyperphosphatemia in patients with rhabdomyolysis 1, 2

Liver function tests should be performed to assess for hepatic involvement and distinguish between hepatocellular and other patterns of injury in patients with rhabdomyolysis 1
Coagulation studies should be evaluated to assess for disseminated intravascular coagulation, which can be a complication of severe rhabdomyolysis 1
Arterial blood gas analysis should be performed to assess for metabolic acidosis, which commonly occurs in severe rhabdomyolysis 1
ECG and cardiac troponin should be used to rule out cardiac involvement, especially in severe cases of rhabdomyolysis 1

Viral studies should be performed if viral myositis is suspected in patients with rhabdomyolysis 1
Autoimmune markers, such as ANA, ASMA, and ANCA, should be tested if autoimmune myositis is suspected in patients with rhabdomyolysis 1
EMG and MRI may be useful in cases of inflammatory myositis to differentiate from rhabdomyolysis 3

Serial CK measurements are important to monitor the course of rhabdomyolysis in patients with this condition 1
Compartment syndrome assessment should be performed in traumatic cases of rhabdomyolysis, with early signs including pain, tension, paresthesia, and paresis 1

In patients with immune checkpoint inhibitor therapy, monitor for myositis with rash as a potential cause of rhabdomyolysis 2
For patients with idiopathic hyperCKaemia, investigation for malignant hyperthermia susceptibility may be warranted 4

Complete electrolyte panel to assess for hyperkalemia, hypocalcemia, and hyperphosphatemia, which are common complications, as recommended by the Kidney International guidelines 5
Renal function tests including blood urea nitrogen (BUN) and creatinine to monitor for acute kidney injury, as suggested by the Kidney International guidelines 5

For severe rhabdomyolysis (CK >5,000 IU/L), monitor CK, electrolytes, and renal function every 6-12 hours initially, as recommended by the Kidney International guidelines 5
For severe rhabdomyolysis, once CK levels begin to decrease, monitoring can be reduced to daily, according to the Anaesthesia guidelines 6

For traumatic rhabdomyolysis, monitor for compartment syndrome with clinical assessment of pain, tension, paresthesia, and paresis, as suggested by the Anaesthesia guidelines 6
In crush injury patients, point-of-care devices like iStat can provide rapid assessment of creatinine and potassium levels when standard laboratory infrastructure is limited, as recommended by the Kidney International guidelines 5
For patients with crush syndrome following disasters, CK levels above 75,000 IU/L are associated with high risk of acute kidney injury (>80%), according to the Anaesthesia guidelines 6
For patients with crush syndrome, ECG monitoring is crucial to detect cardiac arrhythmias, particularly in the setting of electrolyte abnormalities, as recommended by the Anesthesiology (ASA) guidelines 7

If using point-of-care devices in disaster settings, be aware that they have a narrow operational temperature range (16–30°C), as noted by the Kidney International guidelines 5

In cases of exertional rhabdomyolysis, recurrent rhabdomyolysis, or persistently raised serum CK with no identified cause after neurological work-up, consider referral for investigation of malignant hyperthermia susceptibility, as recommended by the British Journal of Anaesthesia 8, 9, 10