Staff in EAPOC Project Trained on GeneXpert Machine
Article by Calvin Mbeda, Adhiambo Phillister, and Frank Angira
The GeneXpert machine is a molecular diagnostic platform developed by Cepheid, a company specializing in molecular diagnostics. It is used for the rapid and accurate detection of various infectious diseases, including providing counts of HIV viral load, also known as viral load testing. The GeneXpert machine tests clinical samples to quickly identify infectious diseases like tuberculosis (TB).
The GeneXpert is a closed-system polymerase chain reaction (PCR) machine that allows you to perform automated, cartridge-based PCR–the gold standard for many diagnostic lab tests. With GeneXpert, a PCR test can be performed within hours, by inserting a disease-specific cartridge into the machine that will detect and amplify specific sequences of genetic material (DNA or RNA), confirming the absence or presence of that disease of interest in the sample. Traditional PCR testing requires a molecular biology lab with skilled technicians and a highly controlled environment. Utilizing the GeneXpert machine allows you to bypass those needs and provides a more “point-of-care" test.
Each cartridge is used for a single PCR test for a specific oncology marker or infectious disease, such as COVID-19, HIV, and more. The cartridges are single-use, self-contained, and contain all necessary PCR testing reagents.
If we want to make an analogy using a pre-prepared meal, the GeneXpert cartridge is the TV dinner, and the GeneXpert machine is the microwave–the only machine that can heat it. The beauty of the cartridge, or TV dinner, is that all ingredients are included, pre-measured, and prepared–you do not need a cutting board or chef knife, and it does not require a trip to the market for the individual ingredients. The level of technical “culinary” skill level is minimized, and finish time is significantly shortened.
From these pictures, during the East Africa Point of Care Viral Load Study (EAPoC-VL) Training, all staff participating in the implementation of EAPOC VL activities attended face-to-face training at the site. A dry run on how the schedule of activities is conducted. This is the testing area; the GeneXpert machine. The laboratory lead, Fred Oloo took us through a demonstration on sample reception, sample preparation, and cartridge loading, where the sample is loaded into a disposable cartridge.
Each cartridge contains all the necessary components for the molecular diagnostic assay, including insertion into the GeneXpert machine, whereby the loaded cartridge is inserted into the GeneXpert machine, which automatically performs the molecular diagnostic assay. The machine's design integrates sample preparation, nucleic acid amplification, and detection into a single automated process, results interpretation, and data management.
