Blood draw · 2 analyses
Cobalt and Chromium
Cobalt and chromium in a single blood draw. For people with a metal-on-metal hip replacement, as an addition to the check-up by the orthopedic surgeon.
€ 96,00
All tests
Metals, toxins and medication · Blood
Cobalt (blood)
Cobalt in blood shows how much metal is released from a metal-on-metal hip replacement, or after exposure at work.
At a glance
- Measured in blood
- In 1 test panel
- No special preparation
Explanation
Cobalt (blood): what is measured?
The analysis measures how much cobalt is in your blood. Cobalt is a metal used, among other things, in alloys for joint replacements and in the hard metal, glass and ceramics industries. In a metal-on-metal hip replacement, metal parts rub against each other; this can release cobalt and chromium particles that end up in the tissue around the hip and in the blood. The kidneys excrete cobalt, so with reduced kidney function the value is higher.
What can it detect?
- Wear or corrosion of a metal-on-metal hip replacement, as part of the check-up by the orthopedic surgeon
- Exposure to cobalt at work
Result
What does the result mean?
Cobalt (blood) too high
In people with a metal-on-metal hip replacement the value is often higher than in people without one; a slightly raised value is then not unusual. A rising or clearly raised value may fit extra wear or a poorly functioning implant. According to the NOV (Dutch Orthopaedic Association), the orthopedic surgeon does not decide on the blood value alone, but on the whole picture of symptoms, X-ray and scan. With a strongly raised value, symptoms outside the hip can occur in rare cases, such as an underactive thyroid, tingling or numbness in the hands and feet, worse vision or hearing and heart problems. Reduced kidney function and exposure at work also raise the value.
Cobalt (blood) too low
A low or unmeasurable value is normal. The body only needs cobalt as part of vitamin B12, so a low result is not a deficiency. With a metal-on-metal hip replacement, a low value fits little wear, but according to the NOV reactions in the tissue around the implant can also occur with a normal blood value.
After an abnormal result
A raised or rising value with a metal-on-metal hip replacement is a reason to contact the orthopedic surgeon. According to the NOV, the check-ups are then done more often and, if needed, extended with an MRI or CT scan of the hip. With exposure at work, follow-up is through the occupational physician.
Reliability
How reliable is the test?
Cobalt in blood says something about how much metal is released, but not about how the tissue around the implant reacts. According to the NOV, there are no internationally accepted normal values; the NOV gives its own cut-off values for checking metal-on-metal implants, and the orthopedic surgeon weighs the result against symptoms and imaging. The laboratory's reference value applies to people without an implant and is therefore not the right measure for someone with a metal-on-metal hip. The trend over several measurements says more than one value. The test is not a check for a disease in people without an implant or exposure.
What can affect the result?
- Reduced kidney function raises the value, because cobalt is excreted through the kidneys.
- Laboratories measure in different units (nmol/l or µg/l) and in serum or whole blood; results can only be compared well if the same method was used.
- During the blood draw, a small amount of metal from the needle or tube can enter the blood, which can raise the result slightly.
- In the first months after an implant is placed, the value is often higher and then falls.
Who it is for
Who is the test useful for?
Useful for
Useful for people with a metal-on-metal hip replacement, as an addition to the check-up by the orthopedic surgeon, and for people who come into contact with cobalt at work. According to the NOV, that check-up also includes an X-ray and a check of kidney function. In people without an implant and without exposure, the test adds nothing. A cobalt allergy (for example to jewelry) is diagnosed with a patch test, not with a blood test.
How common is it?
According to a survey of 95 Dutch hospitals, more than 8,400 metal-on-metal hip replacements had been placed up to 2012. Since the NOV advice of 2012 they are hardly placed anymore. Symptoms caused by cobalt outside the hip are rare.
Ned Tijdschr Geneeskd 2012 (Dutch Poisons Information Center, NVIC) and LROI (Dutch Arthroplasty Register)
Drawbacks and risks
- A result above the laboratory's reference value can cause unnecessary worry, while that value is not the right measure for people with a metal-on-metal implant.
- A normal value can be falsely reassuring, because reactions around the implant also occur with a low blood value.
Get tested
Cobalt (blood): test panels
Cobalt (blood) is part of these test panels. You order online and have your blood drawn at a collection point or collect the sample at home.
Evidence
Sources
This explanation is based on Dutch guidelines and independent information. It is general information, not a diagnosis. Discuss an abnormal result with your GP.
More about risks and results- Nederlandse Orthopaedische Vereniging (NOV): Advies metaal-op-metaal heupprothesen per 1 augustus 2015
- LROI: NOV-advies tegen grote kop en resurfacing metaal-op-metaal heupprothesen terecht (Nederlands Tijdschrift voor Orthopedie, 2020)
- RIVM: Heupimplantaten
- Dijkman e.a. (NVIC, UMC Utrecht): Kobaltvergiftiging door metaal-op-metaalheupprothese. Ned Tijdschr Geneeskd. 2012;156:A4983
More explanations
Other tests: Metals, toxins and medication
- 11-OH-THC
- Aluminum (blood)
- Aluminum (urine)
- Amphetamines (urine)
- Arsenic (blood)
- Arsenic (urine)
- Arsenic in hair
- Barbiturates (urine)
- Benzodiazepines (urine)
- Cadmium (blood)
- Cadmium (urine)
- Cannabis screening (THC)