Many diagnostic tests for infectious diseases use a technology called polymerase chain reaction (PCR) to determine if a patient is infected with a virus or other pathogen. PCR-based testing works by amplifying a very small amount of genetic material to create millions to billions of copies so that there is enough for it to be detected and analyzed.
PCR testing — particularly when using high throughput instruments — requires far more than just the test itself. There are actually several different consumables required to get to the result, which we break down for you here.
Sample Collection Components: Materials required for collecting a sample from a person’s throat or nose:
|Nasal swab used to collect the sample by a healthcare provide. Sample collection swabs are designed speciﬁcally to be used for PCR testing and differ from household cotton swabs such as Q-tips|
|Testing tube containing a solution called viral transport media that protects the integrity of the sample within the tube during transport to the lab|
|Common laboratory tool known as a pipette used to transfer the sample from the collection tube into a secondary tube where it will be readied for analyzation with other patient samples. Note that not all samples need to be pipetted, as this depends on the type of test.|
Test-Speciﬁc Components: Ready-to-use test kits that include all the components needed to extract the RNA from the patient sample and optimize it for PCR. Each kit includes:
|A premixed solution, called a PCR master mix, that contains a complex blend of biochemicals, called reagents, and other components necessary to run the PCR test|
|Essential compounds to multiply and amplify the genetic material|
|Positive and negative controls that are run with every batch to ensure the test is functioning properly|
Non-Speciﬁc Test Components: Also known as omni reagents because they are test agnostic
|Manufacturer-speciﬁc racks for holding sample tubes, pipette tips to transfer samples onto processing and ampliﬁcation plates. Up to 96 samples can be processed on a single plate|
|Manufacturer-speciﬁc chemicals that are typically kept readily available in labs as they are used for many kinds of tests used to detect pathogens – from HIV to the human papillomavirus (HPV) to SARS-CoV-2. They are used to prepare the sample for analysis by breaking open the cell, extracting the RNA and purifying it|