Ammonium ion

Alternative names:

ammonia - test; NH4+

What the risks are:

• excessive bleeding
• fainting or feeling lightheaded
• hematoma (blood accumulating under the skin)
• infection (a slight risk any time the skin is broken)
• multiple punctures to locate veins

Special considerations:

This test is about 90% accurate.

Patients with liver disease may have clotting problems. After the venipuncture, pressure may need to be applied to the puncture site for several minutes to ensure that bleeding has stopped.

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.