Doctor Yeh says tests with human blood can produce the wrong results, so they are not dependable.

VOA: special.2009.08.03

But she says in a real lab, experts would use pig blood to conduct their tests.

VOA: special.2010.05.05

In developed countries, microbiologists do these tests with blood from wool sheep or horses.

VOA: special.2009.08.03

The first involves sheep. Researchers have found that hair sheep are a good source of blood for use in tests to diagnose infectious diseases in people.

VOA: special.2009.08.03

So tests often use human blood instead.

VOA: special.2009.08.03

They also did ultrasound and other tests to measure blood vessel function and the thickness of the artery wall.

VOA: standard.2010.03.04