By Kate Hunger
Carrie Bartosh is a laboratory supervisor in the Microbiology Department at University Hospital in San Antonio, where she oversees day-to-day operations and performs testing within the Immunology, Virology, and Molecular sections. She earned a bachelor’s degree in clinical laboratory sciences from UT Health San Antonio and is certified as a medical laboratory scientist (MLS) with a specialty in virology.
Read Bartosh’s insights below on the education and expertise an MLS brings to the medical team, as well as her experiences during COVID-19 testing.
The role of the medical laboratory scientist
MLS provides essential data to aid diagnosing patients and is a vital member of the health care team. They use sophisticated instrumentation as well as intricate manual processes to perform complex tests on a variety of patient specimens including blood, urine, CSF, and other body fluids. They work in a range of settings, from hospital and physicians’ office laboratories to veterinary clinics, laboratory computer information systems, and the food industry.
The laboratory produces 70% of the data that is used for clinical decision-making. Medical laboratory scientists are the analytical backbone of the medical team. While we know that each sample is a patient, we are able to put emotions aside and evaluate the data to ultimately ensure quality results are available to the provider.
MLS education, training, and certification
Medical laboratory scientists earn a bachelor’s or a master’s degree and have a solid background in biological and chemical sciences.
• The last two years of their education are specialized studies of human physiology and the disease processes and external factors that affect them.
• Following their coursework and clinical rotations, they take a comprehensive certification exam to demonstrate their mastery of that knowledge.
My degree in medical laboratory science gave me an understanding of each of the disciplines in the clinical laboratory and how they overlap. Looking at the big picture can prevent the reporting of erroneous results. A molecular test for bacteria in the CSF, for example, should not be released if it doesn’t correlate with the microbiology and chemistry results.
Technology is ever-changing. I see medical laboratory scientists learning increasingly sophisticated instrumentation; they will need to be mechanically inclined and have a solid understanding of the basic underlying science. Without a fundamental knowledge of what we call the “gold standard” assays, medical laboratory scientists will be at a loss when it comes to troubleshooting.
The role of MLS in COVID-19 testing
I have been involved in the initial testing of the COVID-19 assays to prove that they work as we anticipate they will (validation) and have written the standard operating procedures and training materials to pass along the knowledge and intricacies of the assays to additional staff. Before we began running any of the assays, I built the test in the laboratory information system so that we would be able to keep up with the rapidly evolving testing platforms.
Since beginning to test for COVID in March, we have seen an increase in our daily test requests. We began by running a batched manual RT-PCR assay testing between 100-250 samples a day. In April we implemented a rapid molecular assay (Cepheid GeneXpert) that produces one result in 45 minutes. We run about 15–20 of these a day. This past week we began running our third COVID assay on Hologic’s Panther. This instrument has replaced the manual assay and offers us a platform that is capable of random-access high-volume testing. With that capability, we are steadily increasing from the 250-sample mark and have been making plans to be able to test 1,000 samples per day.
When performing COVID tests, we isolate the nucleic acid (DNA and RNA) from clinical samples through a series of wash steps. Once we have that, we introduce short sequences of the SARS CoV-2 genome along with enzymes and nucleic acids to make more of the viral sequences. Labeled probes allow us to visualize the amplification process by measuring usually a fluorescence or chemiluminescence.
The biggest obstacle for us regarding COVID-19 testing has been obtaining collection materials and testing reagents. From the beginning, we have had a great partnership with UT Health who has been instrumental in overcoming these hurdles. One amazing outcome of this partnership has been the in-house production of viral transport media, so we don’t have to vie for this crucial supply with the rest of the world.
A range of tests performed
As far as molecular testing in the microbiology department, we have rapid testing that can produce a result in an hour or less on our Biofire and Cepheid GeneXpert platforms. Biofire runs multiplex syndromic panels to detect and differentiate up to 27 targets (organisms and antibiotic resistance genes) that are common pathogens for that specimen type. We run the Respiratory Panel, the Gastrointestinal Panel, the Blood Culture Identification Panel, and the Meningitis/Encephalitis Panel. In addition to SARS CoV-2 on Cepheid, we run the Flu A/Flu B/RSV, C. difficile, Group B Strep, SA/MRSA, M. tuberculosis, and CARBA-R assays.
- Our Roche Ampliprep/Taqman system tests blood samples for HIV, Hepatitis C, and Cytomegalovirus viral loads.
- The Luminex ARIES instrument is used for BK Virus and Epstein Barr Virus quantitative assays as well as qualitative Herpes Simplex Virus 1 & 2 from mucocutaneous swab samples.
- We use Hologic’s Panther instruments to test not only for SARS CoV-2, but also for Chlamydia/N. gonorrhea, Human papillomavirus (HPV), and Zika Virus.