Chromium (blood)

Values in the general population are very low (below about 20 nmol/L, and below 10 on some methods); the main use today is in people with a metal-on-metal hip replacement, where the MHRA threshold that prompts closer follow-up is 7 ug/L, about 134 nmol/L, and the printed cut-off is the one to use.

Chromium is a metal that the body may use in tiny amounts in handling sugar, though this remains uncertain. In practice the blood test is used to look for chromium released from metal-on-metal hip replacements, and, less often, for exposure at work in plating, welding, tanning and cement. Blood chromium reflects exposure over the previous few months.

It is requested, together with cobalt, in the routine follow-up of people with a metal-on-metal hip replacement or resurfacing, following MHRA guidance, and in people exposed at work. It is rarely a nutritional test.

• Wear from a metal-on-metal hip replacement, hip resurfacing or some other metal implants
• Work with chromium plating, stainless steel welding, leather tanning, cement or pigments
• Chromium supplements sold for blood sugar or weight loss
• Long-term kidney disease, which slows its removal
• Contamination from an ordinary stainless steel needle or tube, which can be enough to matter at these tiny concentrations

• A value below the cut-off is the expected finding
• Removal or revision of a worn metal implant, after which the level falls over months
• Ending the exposure at work

• The concentrations involved are so small that a standard needle or tube can contaminate the sample, so a trace-element tube and special technique are needed
• A well-functioning metal-on-metal hip gives a modest rise that is expected and simply monitored
• Different methods and sample types (whole blood, serum, plasma) give different numbers

A whole blood or serum sample in a trace-element tube, collected with a technique that avoids stainless steel contamination, no fasting needed. In people with a metal hip it is usually paired with cobalt and repeated at set intervals.

Written by a UK consultant physician. Typical UK adult reference ranges; your laboratory's own printed range takes precedence.