A more accurate method to measure iron in clinical samples is proving ahead of its time, say researchers in Spain. 

The group at the University of Oviedo in Spain, led by Alfredo Sanz-Medel, has developed a technique that allows many variables that can indicate iron-related disease to be measured simultaneously and with great precision.

Any imbalance in the amount of iron in the body can lead to disease, said Sanz-Medel. But many different parameters need to be measured to detect such pathologies - since the metal is used not just as an oxygen transporter in the blood but also in numerous enzymes and processes throughout the human body. Until now these parameters have had to be measured separately, often needing multiple steps.

Sanz-Medel's method avoids this and uses transferrin (Tf), a blood plasma protein that transports iron around the body, to measure iron levels in serum. The group saturate the transferrin with either naturally-occurring iron or a non-radioactive isotope and use high performance liquid chromatography (HPLC) and inductively coupled plasma-mass spectrometry (ICP-MS) techniques to measure the amounts of the metal and protein. By comparing the iron isotope ratios, the data can be used to extrapolate clinically useful parameters including the amount of iron bound to Tf and unbound in serum.

Complementary experiments using ICP-MS can evaluate clinically useful paramters.

Group member María Montes-Bayón explained the team's approach: 'A great number of biomedical applications use radioactive isotopes. The main advantage of stable isotopes, especially for in vivo studies, is that it means no radiation hazard for the patients.'

Zoltan Mester, an expert in using mass spectrometry in isotope ratio analysis, from the Institute for National Measurement Standards in Ottawa, Canada, described the work as a 'dramatically new approach for the study of iron homeostasis.' In fact, the work is so novel that Montes-Bayón admits that the challenge now is to convince the medical community that 'new and more specific tests are necessary to detect increasing numbers of diseases.' With this aim, the group is now looking to start collaborating with biochemists and medical doctors to further the work.

Laura Howes