What is the difference between a metal sensitivity test and a metal ions test?
A metal sensitivity test can be done to see if a patient has an allergic response to one of the metals in the implant. It can be done before or after the surgery. An ion test is done to measure the amount of cobalt and chromium metal ions in the blood or urine –it is done after the surgery has been done to check if it is working well, i.e. producing low wear and low ion levels or high wear and high ion levels. 10). How are they done? The sensitivity test can be in the form of a small patch containing metal compounds applied to the arm or back for several days, or a blood test where white blood cells are exposed to the metals of the component. The ion test requires a blood or urine sample, usually 3 tubes of blood and preferably a full 24 hour collection of urine. Only certain specialized labs do these tests, and they are mostly done as part of a research study, so they are not readily available to all patients, although surgeons can often arrange to have them done. 11). How accurate ar
