Diagnosis

To diagnose ascariasis, your doctor may review your symptoms and order tests.

In heavy infestations, it's possible to find worms after you cough or vomit. The worms can come out of other body openings, such as your mouth or nostrils. If this happens to you, take the worm to your doctor so that he or she can identify it and prescribe the proper treatment.

Stool tests

Mature female ascariasis worms in your intestine begin laying eggs. These eggs travel through your digestive system and eventually can be found in your stool.

To diagnose ascariasis, your doctor will examine your stool for the tiny (microscopic) eggs and larvae. But eggs won't appear in stool until at least 40 days after you're infected. And if you're infected with only male worms, you won't have eggs.

Blood tests

Your blood can be tested for the presence of an increased number of a certain type of white blood cell, called eosinophils. Ascariasis can elevate your eosinophils, but so can other types of health problems.

Imaging tests

• X-rays. If you're infested with worms, the mass of worms may be visible in an X-ray of the abdomen. In some cases, a chest X-ray can reveal the larvae in the lungs.
• Ultrasound. An ultrasound may show worms in the pancreas or liver. This technology uses sound waves to create images of internal organs.
• CT scans or MRIs. Both types of tests create detailed images of the internal structures, which can help your doctor detect worms that are blocking ducts in the liver or pancreas. CT scans combine X-ray images taken from many angles. MRI uses radio waves and a strong magnetic field.