Department of Biology

Indiana University’s plan to operate its own COVID-19 mitigation testing labs became a reality on October 21, 2020, when the testing facility in Myers Hall on the Bloomington campus processed its first run of tests.

Distinguished Professor of Biology Craig Pikaard serves as the lab’s scientific director and oversees the testing operations run by a team headed by Laboratory Supervisor Dr. Sumitha Nallu and Laboratory Manager Dr. David Merritt. Professor of Biology Matthew Hahn serves as the overall director of the facility, handling compliance issues as a CLIA-certified clinical laboratory as well as personnel management.

IU operates two other testing labs at the IU School of Medicine on the IUPUI campus. Pikaard lab members, Dr. Akihito Fukudome and Dr. Pascal Martin spearheaded the effort to establish the testing protocols now in use in all three labs, with Pikaard lab member Dr. Ramya Enganti and Innes lab members, Dr. Brian Rutter and Hana Karimi also involved.

The director of IU mitigation testing, Dr. Aaron Carroll of the IU School of Medicine, credits the testing as a key piece of keeping COVID-19 cases low in the campus communities. “With these new labs,” said Carroll, “I’m excited to be able to further enhance our mitigation testing with more frequency and including a larger number of people in each week’s sample group.” Performing its own testing allows IU to spot any trends and take appropriate public health actions in a much more timely manner to avoid outbreaks.

The sample tubes are then placed in a Hamilton STARlet liquid handling robot, which is on loan to the facility from Eli Lilly until two new STARlet robots being built in Reno, Nevada, arrive—expected in early December.

The Hamilton robot transfers 376 saliva samples into four 96-well plates (8 additional wells of these plates are used for controls, half negative and half positive) and mixes the saliva samples with a solution containing detergent to liberate the RNA from SARS-CoV-2, the coronavirus which causes COVID-19.

The four 96-well plates are then moved to an Agilent Bravo robot, which transfers a tiny amount of liquid (5 microliters) from each well of the four 96-well plates into a single 384-well plate. The Bravo robot also mixes in an equal amount of testing reagents that allow the detection of viral RNA.

The first reaction copies any coronavirus RNA into DNA. The DNA corresponding to three different viral genes is then amplified through 40 cycles of DNA replication, doubling the amount of DNA with each cycle. The amplification process results in fluorescent products of different color for each gene target, if present. These fluorescent signals are measured after every cycle and displayed on the screen of the thermal cycler as it runs.

Positive samples display amplification curves that are absent in negative samples and rise well above background signals.

“It’s easy to tell whether a sample is positive or negative most of the time,” Pikaard said. “But, there are inconclusive results sometimes.” There won’t be as much coronavirus in the system of someone who has either had COVID-19 and is getting over it or someone who has just been infected. Because of possible inconclusive results, the saliva samples are kept until a run is completed so that samples can be run again, if necessary to get a clear result. The samples are then sterilized and safely disposed of afterward.