Toxicity Screening for Giardia duodenalis (Giardia lamblia) by Immunoassay

Your doctor may order this test if you have ongoing diarrhea, stomach cramps, bloating, or other digestive problems that could be caused by Giardia, a tiny parasite that lives in the intestines. Testing may also be recommended if you recently drank untreated water from a lake or stream, traveled to an area where Giardia is common, or had close contact with someone who has symptoms. It can also be used to confirm that treatment has cleared the infection.

Your doctor may recommend this test if you’ve recently traveled to areas with poor sanitation, have unexplained diarrhea, or show symptoms like stomach pain, gas, or loose stools that don’t improve with usual treatments. It’s also used to confirm a suspected Giardia infection in people with ongoing digestive issues.

Before the test, tell your doctor about any medicines you are taking, especially antibiotics or anti-diarrheal drugs, because these can affect the results. You may be asked to pause certain medications for a short time before your stool sample is collected. The lab will give you a collection kit and step-by-step instructions. In most cases, you can eat and drink normally, but be sure to follow any specific directions your doctor provides.

No special preparation is needed. You’ll provide a stool sample in a container provided by your lab. If you’re using a home collection kit, follow the instructions carefully to ensure the sample stays fresh and accurate.

If the test finds Giardia parasites or proteins in your sample, it usually means you have an active Giardia infection, which is most often treated with prescription medication. A negative result may mean you are not infected, but because the parasite is not always shed in every stool sample, your doctor may order repeat testing if your symptoms continue. Your doctor will review the results with you and recommend the best next steps.

Positive results indicate the presence of Giardia parasites in your stool, suggesting an infection. Negative results mean no parasites were detected in this sample, but infection could still be present. Repeat testing may be needed if symptoms continue.

Giardia infection often causes watery or greasy diarrhea, stomach cramps, bloating, and excessive gas. Many people also experience nausea, loss of appetite, fatigue, or weight loss, because the parasite interferes with the body's ability to absorb fats and nutrients from food. Symptoms typically appear one to two weeks after exposure and can last for several weeks or longer if the infection is not treated.

Symptoms may include watery diarrhea, stomach cramps, bloating, gas, nausea, or a foul-smelling stool. Some people may have mild or no symptoms at all. Symptoms can range from a few days to several weeks.