Cobalt is an essential element found principally in vitamin B12 (cyanocobalamin), a cobalt complex. Determination of nutritional adequacy is therefore more conveniently assessed through measurement of vitamin B12. Measurement of cobalt for nutritional purposes has little value. Measurement of cobalt and chromium in whole blood is used to assess the viability of prosthetic implants especially in younger adults.
Exposure to cobalt and its compounds occurs in the hard metal industry, cobalt refineries, specialist alloy manufacture, magnet manufacturing, the paint industry, and in diamond tooling. The main effects noted in humans result from dust inhalation and skin contact. Prolonged inhalation can result in respiratory sensitisation and asthma, and skin contact can lead to allergic dermatitis. Although it does not accumulate in the body, chronic ingestion of cobalt can result in cardiomyopathy.
Measurement of urinary cobalt concentrations on samples collected at the end of a working shift can be used as a guide to exposure. It has a very short half-life and after exposure urine concentrations can drop to normal in 2 to 3 days.
Measurement of chromium and cobalt in whole blood is used to assess the viability of prosthetic implants.
Sample Requirements and Reference Ranges for Cobalt
| Sample Type | Whole blood, random urine |
|---|---|
| Container | EDTA, universal container |
| Precautions | Urine samples for occupational exposure should be taken as random samples at the end of a working shift. |
| Minimum volume* | Whole blood: 250 µL Urine: 1 mL |
| Reference ranges | |
| - whole blood | < 50 nmol/L MHRA action limit: 120nmol/L (7 µg/L) |
| - urine | < 1.6 nmol/mmol creatinine |
| Turnaround time | 2 weeks |
| Method | Urine: Graphite furnace/atomic absorption spectrometry
Blood: Inductively coupled plasma mass spectrometry |
* This is the absolute minimum volume; these volumes are insufficient to carry out a repeat analysis in the event of an analytical problem.