Why Do Your Lab Samples Get Contaminated?

Lab Samples

Are you a molecular biology lab owner? It is a common issue that samples get contaminated which causes inaccurate results and a lot of hassle. You should first find the root cause to get rid of this contamination. After a detailed analysis of all the possible causes, you should take adequate preventive measures to avoid contamination in the future. In this blog, we will share the potential causes of contamination in your laboratory samples and also offer remedies to prevent them. Some of the sources of contamination in your lab are;

Unsealed Samples

A sample that is not appropriately sealed is prone to catch contamination from the environment. Changes in temperature, humidity levels, and light exposure (if the sample is photosensitive) are enough to contaminate the sample, and it won’t give accurate results even after a bit of exposure. You should keep the sample sealed tightly when you are ashing in muffle services, drying in hot air ovens, or storing them in refrigerators. A sealed sample will not catch any contamination and give you accurate results. So one essential step to keeping your lab contamination free is keeping samples sealed at all costs.

Sample Container

It is a common practice in molecular labs to keep all the samples in inert containers. These containers are unable to react with the sample and change its composition. You should also make sure all of your containers are inert. You should buy your molecular biology products from an authentic seller who sells inert containers that don’t contaminate your sample. Whether you are buying PCR plates for ABI, pipettes, or storage bottles, all of them should be of high quality so that they won’t be a reason for altered lab results.

Sampling Tools

Unclean sampling tools can also be a reason for the samples’ contamination. When you are handling the samples, you must sterilize all the tools properly. Wear fresh gloves every time you are handling the sample. It is best to keep separate sampling tools for different sampling requirements. You should keep a set of sampling tools for each sample in a properly sterilized drawer and wear proper gloves, caps, and masks before opening the drawer. The sampling tools must be kept clean to save the lab from contamination.


Cross-contamination happens when other samples contaminate one sample. Cracked containers, close proximity, or untidy work practices can cause cross-contamination. It can also occur when you accidentally use the same spatula for two different samples. The traces of the first sample left on the spatula will react with the second sample and contaminate it. While collecting the samples and making dilutions, you must use a fresh and clean pipette with LTS pipette tips. That is why you should be very careful in the molecular laboratory, as your little carelessness can cause alteration in your results which you don’t want.

Sub-Standard Reagents

Reagents are needed in the laboratory to carry out the experiments. If you buy low-grade reagents, they can also cause contamination in your samples. You should be very careful in buying your reagents and always purchase from authentic dealers. High-quality reagents will ensure accurate results in your lab.

Contamination From The Analyst

The analyst could be the one who is causing contamination in the samples by not following proper hygiene protocols. At all times, when in the lab, an analyst should wear safety gear, including gloves, caps, and a face mask. Contamination from the analyst should never be overlooked, and proper hygiene protocols should be followed to keep the results highly accurate.

Bottom Line

If you face contamination issues in your laboratory, look for these factors. You must be lacking one or more of these, which are the cause of contamination. Do a thorough check, and you will find the reason. Once you find it, it will be easy for you to avoid that mishandling and make your lab results high in precision.

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