This site is very good and says 3 tests can detect it so if you have the symptoms, definitely talk to your doc
The major symptom of acute giardiasis, mainly seen in travelers, is protracted diarrhea. The incubation period for infection is generally 9-15 days. The acute stage usually begins with a feeling of intestinal uneasiness followed by nausea and anorexia.1 Low grade fever and chills may occur. These symptoms are followed by watery, foul-smelling, explosive diarrhea, abdominal pain, passage of foul gas and belching. This stage lasts for 3-4 days, often resembling other causes of travelers' diarrhea, so giardiasis may go undiagnosed. If left untreated, symptoms may persist for months. Malabsorption due to chronic Giardia infection has also been reported.
Other common symptoms of giardiasis include abdominal pain, flatulence, bloating, vomiting and weight loss.2 Symptoms vary from person to person, often depending on the inoculum size, duration of infection, and individual host and parasite factors.1 The diarrhea can be mild and produce semi-solid stools, or it can be intense and debilitating.