You are here: MEDICA Portal. Magazine & More. MEDICA Magazine. Archive. Blood.
"The Test Describes a Trend - not Actual Amounts"
The longer the hair, the further
one can look back in time
MEDICA.de talked to Kristin Gellein, PhD from the Department of Medicine of the Norwegian University of Science and Technology, about a newly developed test, its advantages and its limitations.
MEDICA.de: Miss Gellein, if I gave you a strand of my hair what could you tell from it using your test?
Kristin Gellein: Since hair grows one centimetre per month and your hair is twelve centimetres long I can analyse trace elements in your hair dating back about a year. I analyse centimetre by centimetre getting a history of trace elements over time which can be related to intake of food or exposure. I would therefore be able to tell you, for example, that you had lower iron levels in January and February when compared to the other months.
MEDICA.de: You are, of course, not the first to use hair as an indicator for substances present in the human blood. Compared with other hair tests what can yours do better?
Gellein: Most other tests analyse the whole hair strand in one piece, not centimetre by centimetre. By doing so you only get an average of trace elements contained in the hair, an absolute number which cannot be set into relation with other numbers. But with my method you can tell a person: The level of, for example, iron is much higher in March than in the other months around it. That basically means that the person’s personal average was higher in March than usual.
MEDICA.de: What are the limits of the test?
Gellein: I cannot tell how much of an element you have taken in exactly since I can only observe changes month by month. If you have high blood levels of, for example, mercury, you will also have high levels of this element in the hair. With analysing the changes in the levels over time, I can see whether somebody has had a huge decrease or increase in certain trace metals and looking at the curve over time I can determine when this started to be so. My test describes a trend, it cannot give actual amounts.
MEDICA.de: But has it not already been possible in forensic science to determine whether somebody was poisoned or took drugs in the past by analysing hair?
Gellein: Yes, it has. These tests have been used to prove the intake of single substances that are usually not contained in the body like drugs or poison. But with my method we are able to measure many toxic and nutritional trace elements at once in very low concentrations. And we have been able to relate our results to
specific exposures and intakes of food, not to influences from the outside, shampoo or wrong washing.
MEDICA.de: How did you manage to do that?
Gellein: I used a newer instrument, the HR-ICP-MS* . Older instruments have not been able to detect low concentrations or more than one trace element. It would have been very time consuming to do it for twelve trace elements** one after the other, and not at the same time as I do with elements such as silver, lead or cadmium. I was able to realise my idea with this new instrument that was built some years ago to analyse trace elements in all kinds of materials.
MEDICA.de: Hair is exposed to the environment, though. How does bleached hair or influences of environmental pollution affect the test results?
Gellein: That is the big problem with hair analyses in general and there are no standardised procedures. For our study, we analysed the hair donor’s shampoo so we knew for which trace elements we should receive higher results than in fact contained in the blood. Also, we washed the hair with household dishwashing liquid before we used it.
We tested our washing method with hair from a married couple from India: the couple lives in an urban area eating the same food and using the same shampoo but with the man always wearing a turban outside meaning that his hair was hardly exposed. The results were that we found no significant difference between the two even for a typical outdoor contaminant. I reason that contamination from the outside is not a big problem for my study and that the washing procedure worked. However, for few elements it did not work and we got outcomes that did not make any sense: magnesium and calcium for example went up and down like crazy in our curves, not giving any reasonable results. But for many others, we could make clear statements.
MEDICA.de: In which areas would it make sense to apply your test?
Gellein: Theoretically, possible fields would be environmental medicine or occupational medicine. But the instrument is not available for everybody, it is very expensive. Our goal was not to create a commercial product but better results for hair analyses.
The interview was conducted by Anke Barth.
* Short for: high-resolution inductively coupled plasma mass spectrometry
** Namely: Ag, As, Au, Cd, Cu, Hg, Fe, Pb, Se, Sr, U, Zn