Robots sort blood specimens

In addition to being an international humanitarian organization, the American Red Cross is the biggest, single blood-collection agency in the U.S. Operating as a nonprofit, the Red Cross supplies blood and blood products to approximately 3,000 hospitals daily. The organization is now using advanced robotic automation linked directly to a computerized laboratory information system database to sort tens of thousands of blood samples each day. Ultimately, this high-tech approach is reducing human error and helping improve productivity and traceability.

Along with every donated pint bag of blood that the Red Cross receives, it also collects several blood samples in test tubes. The bag and all of the samples are bar-coded for identification and tracking purposes. Before any blood or component products, such as platelets, red cells, plasma or cryoprecipitate, can be used, samples from each unit must be centrifuged, blood-typed and tested for a variety of viral diseases. This testing is performed at one of five National Testing Laboratories (NTLs) that serve the 36 collection regions encompassing the U.S. and Puerto Rico. Test results are electronically transferred to the blood centers via laboratory information systems.

One of the test tubes from each blood donation is also sent to the newly formed Red Cross Plasma Sample Management Facility located in Birmingham, AL, where the bar-coded samples are centrifuged, frozen and stored for a specified number of days. Test results from the NTLs are matched with samples at the plasma facility using the laboratory-information system database. Based on these test results and other information, the tubes then are sorted into categories for processing. The customer receives acceptable test tubes, performs additional testing and ultimately uses acceptable product to manufacture blood-derived products.

Before the Red Cross had the robots, various people at each of the five NTLs would spend part of their day sorting the tubes manually. This involved scanning the tubes into the system by passing each tube in front of a stationary bar-code scanner. Audio and visual signals indicated whether the sample was good or bad, and an operator interface indicated the proper sort category for each tube. When the Red Cross consolidated this activity from the five NTLs into one site, it became obvious that this sorting process needed to be automated.

Sorting 30,000 tubes/day

The Plasma Sample Management Facility needed a system capable of sorting up to 30,000 specimen tubes a day. The goal was to reduce manual handling of potentially hazardous biological specimens and also to reduce direct-labor hours dedicated to specimen sorting.

In addition, management wanted to improve traceability and eliminate sorting errors.

The challenge was to find an automated solution with the capability to accurately sort tubes according to bar-code labels, based on a direct link with the laboratory information databases. The plasma facility wanted the capability to sort tubes to multiple targets and cells that could operate without interruption for tray and rack loading and unloading. Additionally, a significant amount of walkaway time was desirable. Equipment also had to be compact to fit within the facility, where floorspace is tight.

For this project, the Red Cross purchased three identical AutoSorter II work cells from Motoman, Inc. (www.motoman.com) that were integrated and programmed by Motoman. Each cell sorts up to 950 tubes/hr and provides 35 to 45 min of walkaway time with no interruption for loading and unloading. The Plasma Sample Management Facility currently requires a sortation throughput rate of 2,700 tubes/hr (900/hr/cell), so the throughput of the installation is 50 tubes/hr faster than the requirement, which provides production capacity for future needs.

Each AutoSorter II cell includes a high-speed, Motoman HM700 Scara robot that provides rapid, reliable specimen handling between input trays, bar-code readers and targets. Each four-axis robot manipulator is equipped with a four-jaw, fail-safe tube gripper capable of handling an array of industry-standard test tubes, which range from 12 to 16 mm in diameter and 75 to 100 mm high. The Red Cross uses 13×100-mm tubes, which is a common size in clinical laboratories. The tubes remain capped throughout the entire sorting process.

Tubes enter the AutoSorter cells via a tray/rack-handling conveyor system that infeeds product in 450-position trays and locates the trays for unloading.

The conveyor system queues emptied trays and loaded 150-position trays on separate conveyors on the outbound side of the system for pickup. Each AutoSorter includes five drawers that contain a total of eight 5x6 target racks (240 possible positions). An operator can service the target trays without interrupting the operation.

The AutoSorter cells are fully enclosed with clear plastic panels or interlocked moveable doors on all system access points. A personal computer-based control system regulates the cell control, and an integrated database from Oracle (www.oracle.com) is used to manage the information. The control system communicates with the laboratory information system to obtain specimen data, improve traceability and eliminate sorting errors.

Four basic categories

On the day that a particular batch is scheduled for processing, 450-count trays of frozen samples are removed from the freezer, placed on large rolling racks and allowed to thaw, so the tubes are at room temperature when they are sorted. They can be out of the freezer for up to 72 hr, but the sorting is done in a small fraction of that time. The AutoSorter cells require very little operator intervention of any sort. One operator is assigned to service all three cells, but this person performs other tasks, as well.

The cells are run by touchscreens and a graphical user interface. The software allows multiple sample collection dates to be imported into any number of sorters. Once these files have been downloaded, the operator loads the 450-count trays with samples on one conveyor, puts empty 150-count trays on another, makes sure the cell has 30-count racks in place at other targets and places a biohazard box under the discard point. The operator then removes trays and replaces them.

An automatic scanner checks bar-codes on the 150-count trays, and an operator uses a hand-held bar-code reader to manually scan 30-count racks prior to loading them into one of the five drawers.

The robot first unloads tubes from the 450-count tray and presents each tube to the stationary bar-code reader, which is mounted above a funnel that leads to the discard container. A gripper rotates each tube 360 deg to ensure a good scan of the label. Based on the bar-code reading from each tube label and the link with the laboratory information database, the robot knows what to do with each tube.

The Red Cross systems currently sort specimen tubes into only four basic categories. The robot drops unacceptable tubes directly into a biohazard container for disposal and places acceptable tubes (qualified samples) into the 150-position tray. It places tubes with bar-code labels that the system cannot recognize into 6x5 racks in one or more of five drawers.

The AutoSorter II cells operate two shifts per day, seven days a week and need little maintenance. The factory acceptance test for the cells was done in 2006, and the cells were installed in Birmingham in October. The Red Cross began using the cells in the live environment to process tubes in mid-February 2007.