NH4+ test
Key points
- This test is used to measure the amount of ammonium ions in a blood sample.
- Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand.
- The area is cleansed with antiseptic and punctured with a sharp needle or a lancet.
- The health care provider may advise you to withhold drugs that may affect test results.
Alternative names
Ammonium ion
Definition
This test is used to measure the amount of ammonium ions in a blood sample.
How the test is performed
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and a tourniquet (an elastic band) or blood pressure cuff is placed around the upper arm to apply pressure and cause veins below the tourniquet to distend (fill with blood).
A needle is inserted into the vein, and the blood is collected in an airtight vial or a syringe. During the procedure, the tourniquet is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.
Infant or young child:
The area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if there is any continued bleeding.
How to prepare for the test
Fast for 8 to 12 hours. The health care provider may advise you to withhold drugs that may affect test results.
Drugs that can interfere with the test include thiazide or loop diuretics, barbiturates, acetazolamide, neomycin, and oral kanamycin. Consult the health care provider before this test if you are taking any of these medications.
Infants and children:
The physical and psychological preparation a parent can provide for this or any test or procedure depends on the child's age, interests, previous experience, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:
- Infant test or procedure preparation (birth to 1 year)
- Toddler test or procedure preparation (1 to 3 years)
- Preschooler test or procedure preparation (3 to 6 years)
- School age test or procedure preparation (6 to 12 years)
Written and revised by
Gerald Hurowitz, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
health.am provides general information, not medical advice. Always consult a qualified health professional about your own health.