From case histories it is known that the toxin is stable as four-month-old pickled quail have been poisonous. Humans vary in their susceptibility; only one in four people who consumed quail soup containing the toxin fell ill. The toxin is apparently fat-soluble as potatoes fried in quail fat have proved poisonous.

Coniine from hemlock consumed by quail has been suggested as the cause, though quail resist eating hemlock. Hellebore has also been suggested as the source of the toxin. It has also been asserted that this evidence points to the seeds of the annual woundwort ("Stachys annua") being the causal agent. It has been suggested that "Galeopsis ladanum" seeds are not responsible.

Migration routes and season may affect quail risk. Quail are never poisonous outside the migration season nor are the vast majority poisonous while migrating. European common quail migrate along three different flyways each with different poisoning characteristics, at least in 20th century records. The western flyway across Algeria to France is associated with poisonings only on the spring migration and not on the autumn return. The eastern flyway, which funnels down the Nile Valley is the reverse. Poisonings were only reported in the autumn migration before the quail had crossed the Mediterranean. The central flyway across Italy had no associated poisonings.

Migrating quail used to be caught and eaten in prodigious numbers (150,000 quail exported from Capri in 1850) but modern farming and droughts in the Sahel have led to a vast reduction in the size of the migrations. Conservation efforts and the availability of farmed quail have also reduced the consumption of these wild birds. Coturnism may well disappear before it is understood.

Compartment syndrome is a clinical diagnosis, i.e., no diagnostic test conclusively proves its presence or absence, but direct measurement of the pressure in a fascial compartment, and the difference between this pressure and the blood pressure, may be used to assess its severity. High pressures in the compartment and a small difference between compartment pressure and blood pressure indicate that the blood supply is likely to be insufficient, and that surgical intervention may be needed.

Disseminated intravascular coagulation, another complication of rhabdomyolysis and other forms of critical illness, may be suspected on the basis of unexpected bleeding or abnormalities in hematological tests, such as a decreasing platelet count or prolongation of the prothrombin time. The diagnosis can be confirmed with standard blood tests for DIC, such as D-dimer.

If an underlying muscle disease is suspected, for instance if there is no obvious explanation or there have been multiple episodes, it may be necessary to perform further investigations. During an attack, low levels of carnitine in the blood and high levels of acylcarnitine in blood and urine may indicate a lipid metabolism defect, but these abnormalities revert to normal during convalescence. Other tests may be used at that stage to demonstrate these disorders. Disorders of glycolysis can be detected by various means, including the measurement of lactate after exercise; a failure of the lactate to rise may be indicative of a disorder in glycolysis, while an exaggerated response is typical of mitochondrial diseases. Electromyography (EMG) may show particular patterns in specific muscle diseases; for instance, McArdle's disease and phosphofructokinase deficiency show a phenomenon called "cramp-like contracture". There are genetic tests available for many of the hereditary muscle conditions that predispose to myoglobinuria and rhabdomyolysis.

Muscle biopsy can be useful if an episode of rhabdomyolysis is thought to be the result of an underlying muscle disorder. A biopsy sample taken during an episode is often uninformative, as it will show only evidence of cell death or may appear normal. Taking the sample is therefore delayed for several weeks or months. The histopathological appearance on the biopsy indicates the nature of the underlying disorder. For instance, mitochondrial diseases are characterized by "ragged red fibers". Biopsy sites may be identified by medical imaging, such as magnetic resonance imaging, as the muscles may not be uniformly affected.