In many industries workers come into contact with substances that enter the body through breathing, absorption or ingestion. Understanding chemical exposure is an important part of protecting the health of a workforce. This is why biological monitoring is so important. Unlike air monitoring, which measures the concentration of a chemical in the surrounding environment, biological monitoring tells us how much of that substance has entered the body.
Why does biological monitoring matter?
Workers who are regularly exposed to toxic substances are at a significantly higher risk of developing an illness in the workplace. Some substances can be absorbed in small concentrations and go unnoticed for years. Biological monitoring can help identify that exposure, allowing for early intervention and the prevention of work related ill health.
Biological monitoring also offers useful information about how well workplace controls are working. If a sample shows higher than expected exposure, it may be necessary to take another look at ventilation, PPE, work practices or the way substances are handled. The findings can also identify where additional training is needed.
Why might I be asked to provide a sample?
Being asked to provide a biological sample can understandably raise questions. Does it mean you have been exposed to something harmful? Does your employer have a concern about your health? In many cases, the answer is much less alarming. Sampling may simply be a routine part of an occupational health programme designed to check that existing safeguards are working.
Workers should be told why a sample is needed, what will be tested and how the results will be used. They should also understand how their information will be handled and who will have access to it. Confidentiality is an important consideration, and sampling arrangements should be explained clearly before the process begins.
What sort of sample is needed?
The type of sample required depends on the chemical being involved and how the body processes it. Urine is commonly used because many chemicals and their breakdown products can be measured in it. For other substances, a blood or breath sample may be more appropriate. Your occupational health provider will explain which sample is required and how to collect it. It’s worth following these instructions carefully. Using the wrong container, contaminating a sample or handling it incorrectly can affect the reliability of the results.
When should I provide a sample?
The timing of a sample matters because certain chemicals behave differently once they enter the body. Some accumulate during a working shift, while others are broken down and removed relatively quickly. A sample collected at the wrong time may therefore fail to give an accurate picture of exposure. There is no single rule that applies to every chemical. The correct timing depends on the substance, the test being used and the sampling guidance. Ideally, sampling should reflect normal working conditions so the results provide a meaningful indication of exposure.
How should I provide a sample?
The process is usually straightforward, particularly when a urine sample is required. You will normally receive a container and instructions explaining how to collect and return the sample. Before handling the container, wash your hands and remove contaminated gloves or protective clothing to reduce the risk of contamination. Collect the sample as instructed, secure the lid and return it using the procedure provided. Avoid transferring it to another container or making changes to the collection process unless you have been told to do so.
In other instances a blood or breath sample may be required. For a blood sample, a trained healthcare professional will take your blood using a needle. If you feel faint during blood tests, ask the person taking the sample to lie you down before they begin and take a few minutes before standing up after the test. For a breath test, a sample is taken by breathing into a device that will indicate if volatile organic compounds and gases have passed into the lungs. For all types of tests, if anything is unclear speak to the person arranging the test.
Does drinking water affect the result?
It can. The amount of fluid you drink affects how concentrated your urine is. Drinking a lot of water may dilute it, while dehydration can make it more concentrated. Depending on the test, this can influence the measured level of a chemical or its breakdown products. Laboratories may take urine concentration into account when interpreting certain results, sometimes by measuring a substance called creatinine. The approach varies according to the test, so it’s important not to assume that every result is adjusted in the same way. The best approach is to drink your usual amount of fluid and follow the sampling instructions. Deliberately drinking excessive amounts of water or restricting fluids to influence a result is not advisable and may make the findings less useful.
What happens after the sample is collected?
Once the sample has been collected, it’s sent to a laboratory for analysis. The results are then interpreted by an qualified occupational health professional. This matters because the numbers do not tell the whole story on their own. The type of chemical, the timing of the sample and the relevant guidance values all help determine what the findings mean. If the result suggests higher than expected exposure, the next step is to investigate why. Employers may need to review how a task is carried out, check protective equipment or assess whether ventilation and other controls are effective. Further monitoring may also be appropriate to see whether changes have reduced exposure.
What are the next steps?
Biological monitoring can reveal information that air monitoring alone might miss, helping businesses make better informed decisions about workplace health and safety. However, collecting a sample is only one part of the process. Its real value lies in understanding the result and acting on it when necessary. When biological monitoring is combined with risk assessments, exposure controls and clear communication with employees, it can help identify problems early and reduce the risk of avoidable harm. Find out more about biological monitoring via the link below:
https://mohs.co.uk/services/occupational-health/health-surveillance/