Widespread testing is crucial for tracking the spread of COVID-19. As of April 19, the United States alone had performed almost 997 million tests for COVID-19 since the outbreak of the pandemic, the highest number of any country. Collectively, the top five testing countries—the U.S., United Kingdom, India, Russia and Spain—have conducted more than 3 billion tests.

The diagnostic test of choice for COVID-19 is a polymerase chain reaction (PCR) test. It is a molecular test that analyzes an upper respiratory specimen, looking for genetic material (ribonucleic acid or RNA) of SARS-CoV-2, the virus that causes COVID-19. The PCR test amplifies small amounts of RNA from specimens into deoxyribonucleic acid (DNA), which is replicated until SARS-CoV-2 is detectable if present.

The world’s leading supplier of PCR tests for COVID-19 is German company Qiagen. The company has developed the compact QIAstat-Dx analyzer, which, in combination with a test cartridge, enables real-time PCR tests to quickly detect pathogen nucleic acids in human biological samples. The instrument can detect more than 20 pathogens, including COVID-19, in a single run in just 60 minutes.

Each small test cartridge contains everything necessary, including solid and liquid reagents, to detect a specific pathogen. The cartridges are simple to handle. A sample is taken from the patient and inserted into the cartridge. Only a few steps are required to insert it into the analyzer. After only one minute, the test can start.

Like all medical devices, the test cartridges must meet high quality standards. To ensure that test liquids do not leak, the cartridges must be absolutely leak-proof. At the same time, production costs must remain as low as possible, since each cartridge can only be used once.

For Qiagen, ultrasonic welding systems are the method of choice for joining the plastic parts inside the cartridge. Ultrasonic welding is fast, reliable, cost-effective and eco-friendly. It obviates the need for adhesives, connection elements or solvents.

Two USP750 ultrasonic welding systems from Telsonic are now in operation at Qiagen’s assembly plant in Barcelona, Spain, where the test cartridges are made. One of the machines was already in use before the pandemic; the second was added due to increased demand. Both are housed in sound enclosures that provide effective shielding for employees. Each day, the devices assemble some 2,000 cylindrical plastic parts for the cartridges. The assemblies are secure and leak-tight.

Telsonic’s USP ultrasonic welding systems can be used to join both small and large parts in a variety of industries. The stable press design can be extended with modules and operated in combination with a TelsoFlex controller and MAG generator to provide maximum process control. A range of welding modes and trigger types enable optimum ultrasonic processing of plastic parts. Welding results are monitored in quality windows and automatically evaluated both graphically and statistically. This guarantees that the test cartridges can be manufactured in large quantities with consistent quality.