The type of samples that you collect for your study is likely to be dictated by the diagnostic test(s) that you plan to use. As well as the type of sample, there are a number of other things to consider when sampling, such as patient and healthcare worker health and safety, and safe and appropriate packaging and transportation to the laboratory. The following resource links aim to provide information that can be adapted to your country and your project. It is important to remember, especially with health and safety, to always comply with your country’s guidelines.
This link from the UK government provides guidelines and practices for sample collection, packaging and transportation.
What type of sample should I use?
The type of sample required depends on what you wish to test. If you are undertaking a test that requires nucleic acid, nasal or oral swabs are generally the best option, as the greatest number of virus particles are found in the lungs and upper respiratory tract. If you are looking to do antibody tests, you will need blood samples.
This publication has compared the RT-qPCR detection of SARS-CoV-2 in different types of clinical sample.
How to collect samples
Nasal and/or oral Swabs
Evaluation of Swabs, Transport Media, and Specimen Transport Conditions for Optimal Detection of Viruses by PCR.
COVID-19: guidance on alternative swab types and transport media.
Information on swab, media types and how to take.
Choosing the best swab material
The Extraction and Recovery Efficiency of Pure DNA for Different Types of Swabs.
Choosing a viral transfer medium
It is important to use the correct media to collect samples. Storing samples in media will preserve any viral particles better than a dry swab and viral transfer media should always be used, never bacterial transfer media.
UK Government guidance on alternative swab types and transport media.
Comparison of viral transport media.
WHO guide for field operations (influenza) on viral transport media.
Throat swab preservation solution.
Choosing the best swab location
Comparative accuracy of oropharyngeal and nasopharyngeal swabs for diagnosis of COVID-19.
Nasopharyngeal Swabs Are More Sensitive Than Oropharyngeal Swabs for COVID-19 Diagnosis and Monitoring the SARS-CoV-2 Load.
Swab sampling technique
It is important that anyone taking a sample from a potentially COVID-19 positive patient be protected from potential infection by wearing PPE. Please follow the link to the Health and safety page/area
How to take a swab | Nasopharangeal swab | UK government guidance for taking swab samples
Protocol for Sampling, storage and viral RNA extraction of swab specimens (University of Tubingen, Germany).
YouTube instructional video - Performing a Nasopharyngeal and Oropharyngeal Swab.
Instructional video – Performing swab sample collection
Collecting blood for antibody tests
Whilst potential exposure to SARS-CoV-2 is accepted to be lower for blood sampling compared to swabs, it is still important to follow the same health and safety principles. Health care workers should still use the appropriate PPE when taking samples from patients.
The WHO guidelines provide recommended steps for safe phlebotomy and reiterate accepted principles for drawing, collecting blood and transporting blood to laboratories/blood banks.