People with McArdle’s have raised CK / CPK. Baseline levels can be approx. 2,000–5,000 IU/L (normal values <190)  and can vary significantly with activity. With episodes of rhabdomyolysis CK can be much higher, even in excess of 100,000 IU/L.
Establish a baseline level for patient by testing several times in the absence of recent injury.
The results of CK tests following a series of injuries will assist the patient to understand how much damage they are doing. This will help them to manage their condition and avoid serious episodes.
Set up a mechanism for the patient to be able to access immediate CK testing when they injure themselves. Abnormal results should be urgently communicated to the patient.
CK tends to peak 24 hours after a McArdle injury, then falls by approx. 30% to 50% per 24 hours.
Be wary of results that do not follow the above pattern, or that are reported as “above” a figure. This may indicate an error by the lab due to a result which is grossly outside the lab’s normal experience.
An unusually high CK level after an injury may alert the patient to consider the need to go to the hospital. (See Medical emergencies, page 9.)
A high CK need not indicate a cardiac event. If there is any concern, cardiac-specific proteins (e.g. Troponin I) give a clearer indication.
 See page 7, reference .
McArdle Disease Medical Overview