Key Takeaway
Differences in hair mineral analysis results between laboratories are most often caused by sample preparation procedures, analytical methods, quality control, and interpretation practices — rather than by the HTMA method itself.
Why Do HTMA Results Sometimes Differ?
Hair Tissue Mineral Analysis (HTMA) is a laboratory method used to determine the concentration of selected elements in a hair sample. In biomonitoring research, hair is considered a valuable biological material because it may reflect long-term exposure to selected minerals and environmental elements.
At the same time, HTMA results may vary between laboratories. This does not automatically mean that the method itself is unreliable. Most often, these differences result from the quality of the laboratory process, sample preparation procedures, the equipment used, and quality control standards.
That is why not only the test itself, but the entire process — from sample collection to final interpretation — is essential.
Stages That Affect the Result
Sample Collection
Proper hair sample collection is the foundation of a reliable result. The most commonly recommended sampling site is the occipital area (back of the head), as close to the scalp as possible.
Important factors include:
- the correct sampling site,
- an adequate amount of material,
- avoiding contact between the sample and metal or contaminants,
- proper labeling of the root end of the hair.
Incorrect sample collection may reduce the reproducibility of the analysis.
Sample Washing
One of the most important laboratory stages is removing external contamination from the sample. Hair may contain:
- dust,
- cosmetic residues,
- environmental particles,
- mineral deposits from water.
Excessive washing may partially remove elements from the hair, while insufficient washing may leave contaminants behind. Therefore, the laboratory should use a standardized sample preparation protocol.
Hair Length
In HTMA, the most commonly analyzed hair segment is 1.5–3 cm from the root. This section usually reflects the last few weeks or months of hair growth.
If laboratories analyze different sample lengths, the results may be difficult to compare, because hair segments farther from the scalp are more exposed to environmental factors.
Hair Dyeing and Chemical Treatments
Hair dyeing, bleaching, perming, or intensive styling may affect the composition of the sample.
Chemical treatments may:
- alter hair structure,
- increase porosity,
- affect the concentration of certain elements.
That is why a reliable laboratory should clearly explain sample preparation rules and take these factors into account when evaluating the material.
Analytical Method: ICP-OES vs ICP-MS
The reliability of the result also depends on the analytical method used.
ICP-OES
ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometry) is one of the most commonly used methods in hair mineral analysis. It allows simultaneous determination of multiple elements and provides good reproducibility when properly calibrated.
ICP-MS
ICP-MS (Inductively Coupled Plasma Mass Spectrometry) offers very high sensitivity and allows measurement of very low concentrations.
In practice, both methods can be reliable if:
- the laboratory uses validated procedures,
- the equipment is regularly maintained,
- quality control systems are in place.
The name of the technology alone does not determine the quality of the result — the overall laboratory standard does.
Equipment Calibration and Quality Assurance (QA)
One of the most important factors affecting HTMA reliability is the quality assurance system.
A reliable laboratory should use:
- regular instrument calibration,
- control samples,
- validation procedures,
- repeatable laboratory protocols,
- internal and external quality testing.
QA standards have the greatest impact on result reproducibility.
For laboratories performing HTMA, experience in working with biological material such as hair is especially important, because hair requires strict process standardization.
At Mineralco laboratory, biological material analysis, including hair, is performed using standardized sample preparation procedures, quality control systems, and validated ICP-OES methods. This approach improves result reproducibility and increases the informational value of the test.
The Importance of Interpretation
HTMA is not a diagnostic test for diseases. It is a biomonitoring and mineral trend assessment tool.
Interpretation of results should take into account:
- lifestyle,
- diet,
- supplementation,
- environmental exposure,
- health history
The most common mistake is drawing conclusions based on a single element without considering ratios and context.
In practice, greater importance is usually placed on:
- relationships between elements,
- metabolic patterns,
- changes over time.
How to Choose a Laboratory
When choosing a laboratory for hair mineral analysis, it is worth paying attention to:
- experience in hair analysis as a biological material,
- the analytical method used,
- washing and sample preparation procedures,
- alibration and quality control standards,
- the clarity of reports and educational materials.
A good laboratory clearly communicates the limitations of the test and does not present HTMA as a diagnostic tool.
People interested in the practical process of hair testing, sample collection instructions, and educational materials on result interpretation can explore the information prepared by LifelineDiag.
Frequently Asked Questions About Differences in HTMA Results
Do different results mean that hair analysis is unreliable?
No. In most cases, differences result from laboratory procedures, sample preparation quality, and interpretation methods.
Is ICP-OES accurate enough?
Yes. With proper calibration, method validation, and process standardization, it is a recognized method for multi-element analysis.
Do dyed hair samples exclude testing?
Not always, but the laboratory should clearly explain sample preparation rules and interpretation limitations.
Summary
Differences in HTMA results between laboratories are most often caused by process quality rather than by the concept of hair analysis itself.
The main factors affecting reliability are:
- proper sample collection,
- standardized sample washing,
- appropriate hair length,
- consideration of chemical treatments,
- equipment quality,
- quality control,
- responsible interpretation.
That is why choosing an experienced laboratory is essential for the informational value of HTMA.
Bibliography
- Kempson IM, Lombi E. Hair analysis as a biomonitor for toxicology, disease and health status. Chemical Society Reviews. 2011.
- Seidel S et al. Assessment of commercial laboratories performing hair mineral analysis. JAMA.
- Bass DA et al. Trace element analysis in hair: Factors determining accuracy, precision and reliability.
Hair Tissue Mineral Analysis (HTMA) is a functional and educational tool. It does not replace medical diagnostics or consultation with a physician.