Laboratories are currently scrambling to define and put into place procedures for dealing with processing and testing of samples from highly infectious patients. The CDC has guidelines for healthcare workers and for laboratories specifically (http://www.cdc.gov/vhf/ebola/hcp/index.html). They also are very willing to help. Because Dallas had actual cases of Ebola, our hospital in Dallas mounted a hospital-wide response, in which the CDC and Texas State and County Health Departments were involved early on and throughout. This blog post describes the plans we instituted.
It quickly became clear that we did not want to transport infectious material through the hospital if we could avoid it, keeping everything infectious isolated in a single area. The hospital cleared an ICU wing which contained two negative pressure rooms, and the laboratory used an ICU room two doors away to create a mini-lab. The entire ICU wing was closed off as an isolation zone. No samples will leave the isolation zone unless they are headed for the CDC or State lab, and those will be couriered directly from the isolation zone.
All testing that can be, will be done on the I-stat in the patient room, including electrolytes, BUN, creatinine, ionized calcium and blood gases. A meeting was held with the ICU physicians who will be treating patients, to ask what testing they could foresee requiring other than those available on the I-stat. Their final list included platelets, CBC and coag tests, and originally also asked for ammonia and liver function tests. The only test we could not provide for them was ammonia. We couldn’t find a way to perform ammonia on a whole blood sample and had decided not to centrifuge any samples due to the possible risks of aerosolizing the sample and additional risks associated with aliquotting samples.
For the coag tests, we chose to use the I-stat PT/INR. Knowing that PT/INR on the I-stat is not FDA approved for anything other than Coumadin monitoring, we performed a full CLIA validation of the PT/INR in order to be able to use it for Ebola patients. Using the I-stat this way causes the PT/INR to become a high-complexity test, therefore only those individuals with appropriate licensure, training and competency will be performing the test at bedside.
Testing other than what is available on the I-stat will be done in the mini-lab set up in the nearby ICU room. It will be performed by lab personnel in full PPE, including PAPR (powered air purifying respirators), 3 layers of gloves, etc, all within the isolation zone. Lab testing in the mini-lab will occur once a day, with a possibility of twice a day. We purchased an Abaxis Piccolo for performing the liver enzymes and a Sysmex pocH-100i for the CBC and platelets. Both these analyzers will be run in the mini-lab room. The piccolo will be run inside a biosafety cabinet (BSC) which was put in the room because the piccolo is not a closed system. Sample pipetting into the piccolo carousel will occur in the BSC.
As far as blood utilization, the plan is to perform a one time, ABO only, blood typing on admission of a patient. A blood bank technologist in full PPE will perform the ABO only blood type manually in the BSC in the mini-lab. This ABO only typing has also been validated on samples allowed to settle rather than being centrifuged. The plan is for any patients to receive type O-negative blood if transfusions are required. However if they should require type-specific blood products for any reason (i.e. shortage of O-negative), it was felt that performing the blood type early before viral titers are really high would be better than waiting.
To work in the isolation wing, personnel must don full isolation PPE, including PAPR, etc, with a multi-step system in place for both donning and doffing the equipment. A buddy system is used throughout, with training on all procedures being continuous. The lab personnel who have volunteered to staff the mini-lab have undergone the PPE training. All of this perhaps excessive care is being taken in order to protect all other patients, as well as all healthcare team members, both lab and non-lab. Although Ebola may never reach our hospital, we live in a world where global travel makes if very likely that we will see patients with this or other highly infectious diseases appear in our facilities. It’s important to be as prepared as possible.
-Patti Jones PhD, DABCC, FACB, is the Clinical Director of the Chemistry and Metabolic Disease Laboratories at Children’s Medical Center in Dallas, TX and a Professor of Pathology at University of Texas Southwestern Medical Center in Dallas.