Do you know all the types of swabs?
Swabs are one of Deltalab’s reference products. We have been manufacturing these sanitary products for more than 30 years. With a clear mission to satisfy the needs of our customers, at Deltalab we work to always meet the highest quality standards for our products, which are used daily in clinics, hospitals, industries, universities, and laboratories in more than 125 countries around the world.
During the last year of the coronavirus pandemic, we have heard the word “PCR” many times. Probably someone we know, a relative, a work colleague or we ourselves have been tested by PCR to detect whether we are carriers of the virus. PCR is a technique used to detect SARS-CoV RNA and stands for Polymerase Chain Reaction. It consists, explained in a very simplified way, in the exponential amplification of RNA to check whether the microorganism sought is present in the sample collected, in this case, the SARS-CoV2 virus.
It all starts in the pre-analytical phase, which Deltalab specializes in. The sample is taken using kits consisting of a swab and a tube with transport media for the virus. These are the necessary components for collecting the sample from the patient and subsequent transport to the laboratory where the analysis will be carried out.
Although we may have heard the acronym PCR every day during the pandemic swabs have been used for a long time for a multitude of techniques and applications. In this article, we explain the types of swabs and their different uses.
Traditional or flocked swabs? With or without media of transport? Which media of transport is most suitable for my purpose?
1. What are medical swabs for?
The swab is a medical device used for the collection of biological samples from the human body and allows for the transport and preservation of the sample.
Some of the most common applications of swabs are:
For the isolation of microorganisms in culture media.
For inoculation of plates by seeding on the surface of the medium, as in the case of antibiograms.
For the preparation of smears, after taking the samples to be observed under a microscope.
For sampling of pre-operative cleaning or
All swabs for the collection of microbiological samples are considered invasive medical devices for temporary use and must comply with the Medical Devices Directive 93/42/EEC.
In the specific case of swabs with transport medium, the tube with medium must comply with Directive 98/79/EC on in vitro diagnostic medical devices.
2. Swab typologies
At Deltalab we manufacture a wide range of swabs:
Swabs without media of transport
Sterile or non-sterile
Individual presentation in tubes, peel-packs, and flow packs for sterile products.
Multiple presentations in bags for non-sterile products.
Traditional brooms with agar transport medium
Flocked brooms with liquid transport media
3. Swab head and shaft
The swab head can be made of natural fibres (such as cotton) or inorganic and inert fibres such as viscose, polyester, and flocked fibres. Each material offers different characteristics to be assessed by the healthcare professional depending on the intended use.
Flocked fibre-headed swabs are suitable for use in conjunction with liquid transport media as they offer the best sample absorption and elution capacity in the liquid transport media.
The swab shaft can also be made of various materials: wood, polystyrene, or aluminium, and is chosen according to the sampling point. In the case of flocked swabs, the shaft is made of polystyrene and there are different shafts and head shapes depending on their use: nasopharyngeal, urethral, paediatric, and standard.
The material and the shaft of the swabs (without means of transport) are intended to allow the collection of the sample to obtain a good return (either qualitative or quantitative) at the time of the analysis in the laboratory. This analysis must be done immediately, as without a media of transport, the viability of the sample over time cannot be ensured.
4. What is the media of transport?
As the name suggests, the transport media is intended to preserve microorganisms during transport and ensure the viability of the sample up to a minimum of 48 hours. This is, in fact, the result of a chemical composition formulated to maintain the microbial load with minimal physiological activity.
In this way, micro-organisms experience very little variation from sample collection to arrival at the laboratory for analysis.
The choice of transport medium depends on the micro-organism to be detected (bacteria or virus), and there are different transport media: Amies, Stuart, Cary Blair, Virus, Vicum, Chlamydia.
5. The flocked swab with liquid transport media
The flocked swab was an important step forward in microbiology as its characteristics make it a much more user-friendly and efficient product, both in PCR and for automation in seeding machines. Microbiological testing laboratories appreciate its many benefits over traditional swabs.
Compatible with new automated inoculation and sample seeding equipment.
Compatible with molecular diagnostic techniques.
It makes it easier to collect, transport and process microbiological samples.
Increased reliability for sample recovery: high adsorption and elution capacity in the medium.
Increased viability of the sample, as it is completely suspended in the medium.
It allows you to obtain different homogeneous inoculate from the same sample.
It is suitable for any work protocol.
Minimises potential cross-contamination: less handling and maximum sealing.
More comfort for the user: conical base for easier shaking and greater stability of the tube with the skirt.
More comfort for the patient, due to the soft covering of the swab.
Standardises the receipt of samples in microbiology laboratories.
Facilitates manual sowing.
Allows direct extension for Gram staining, as the medium does not contain agar.
Guarantees the transport and storage of samples at room temperature (20ºC – 25ºC) and refrigeration temperatures (4 – 8ºC).