The initial test for suspected porphyria depends on the symptoms. For acute porphyria with abdominal pain or neurological symptoms, a urine test for porphobilinogen (PBG) is the go-to screening method. If skin symptoms are present, doctors typically test blood plasma or urine for elevated total porphyrins. For light sensitivity without blistering, a blood test for erythrocyte protoporphyrin is used.

If initial tests are positive, further testing is needed to determine the specific type of porphyria. This may involve measuring different porphyrins and precursors in urine, blood, and stool samples. The pattern of which chemicals are elevated can point to the exact enzyme deficiency causing the porphyria. Genetic testing can also be done to identify the specific gene mutation responsible.

Porphyria test results can be complex. Normal levels of porphyrins and precursors can vary, and slight elevations may not always indicate disease. It's crucial that tests are performed at specialized laboratories with experience in porphyria diagnostics. Results should always be interpreted in the context of clinical symptoms and other medical information.

Understanding porphyria testing can help ensure a timely and accurate diagnosis, paving the way for proper treatment and management.