(Normal range: 28-41 mg/dl (0.28-0.41 g/L
Comment: Deficiency of this enzyme is the most common genetically determined abnormality of complement. Patients usually present with recurrent angioneuotic oedema and /or the urticaria. If symptoms are confined to the gut the patient may present with a recurrent syndrome suggesting intermittent intestinal obstruction. Cyclosporin A treatment may inhibit the enzyme
Sample: Citrated plasma