The cobalt ladder

I repeatedly get questions on what levels of  Cobalt are toxic.  I have never seen the word toxic used by anyone.

Here is the Cobalt ladder:


1ppb
physiologic

2ppb
upper normal limit for patients with hip resurfacing

5ppb
abnormal ware

10 ppb
60% show ARMD (adverse reaction to metal debris) within 3 years

20ppb
metalosis

(remember ppb and micrograms per liter are the same.)

Here is another post you might look at:

http://www.mydepuyhiprecall.com/2011/06/is-there-accepted-cut-off-level-for.html

The identification of high serum levels of metal ions is an indication that the hip is functioning poorly.

2. There is no accepted cut off level [of what is bad or really poor.]

3. There is an overall consensus that the blood cobalt or chromium level of a well functioning hip is is approx 2 ug/l (which is the equivalent to 2 parts per billion.)

4. There is a correlation between the metal ion concentrations of serum and component wear.

5. Serum chromium ion levels of greater than 17 parts per billion and serum cobalt ion levels of greater than 19 parts per billion are likely to be associated with metalosis.

6. Elevated metal ion levels have been used to identify patients with metalosis, pseudo tumors and the like.

7. Blood levels are doubled in in painful hips compared with well-functioning hips.

8. Other studies have found that by using a cut off of 4 parts per billion, the cases of problem issues rose from 75% to 90%.