Take 5: Inaccuracies in iron testing

What are some of the causes of inaccurate results regarding iron studies?

Iron deficiency can be diagnosed through blood tests that measure the serum ferritin level but these tests are not always accurate.

“The main inaccuracy with iron studies is [from] people who don’t draw the blood fasting,” says Dr Pradeep Jayasuriya, a GP and the past director of research at the RACGP in Western Australia.

“You need a fasting blood level to get an accurate serum iron.”

Ferritin levels can be falsely raised when a patient is unwell. “Ferritin … is an acute phase reactant so any illness that causes inflammation will raise the ferritin,” says Dr Jayasuriya.

“If you think about this in general practice, people come to us when they are sick. We send them off for a blood test so the ferritin is often raised. So you need to take that ferritin with a grain of salt.”