On the Prospect of CLIA-Waived Differentials

On the Prospect of CLIA-Waived Differentials

Hematology testing such as complete blood counts (CBC) and differentials is customarily the domain of clinical laboratories. Instrument automation and the innovation of compact, streamlined models, however, has made such testing possible outside of the lab. Today’s hematology analyzers range from autoloaded, high-throughput and flow cytometry-capable in the lab to closed-menu, benchtop and ease-of-use at a clinic or physician’s office. While labs in the developing world continue to fuel market growth, avenues to market expansion among clinical and commercial labs in North America, Europe and Japan are limited by the region’s established analyzer bases. Remaining options for growth among hematology vendors include point-of-care (POC) and physician office laboratory (POL) hematology testing. In the United States, the world’s largest IVD market, significant demand exists for products able to provide hematology testing capabilities in POC/POL settings, but without the costs and regulatory requirements of a traditional analyzer.

In vitro diagnostic testing outside of a clinical or commercial laboratory requires certification commensurate with the complexity of the test procedure and analysis of its results. Already a core IVD segment, hematology testing in the United States could be broadened and intensified during routine outpatient care through associated tests’ waiver from CLIA regulatory oversight (Clinical Laboratory Improvement Amendments of 1988). Healthcare professionals performing only CLIA-waived tests in the United States need only to obtain a Certificate of Waiver (COW); use of a hematology analyzer requires higher certification for moderate and high complexity testing.

The U.S. POL market already features a significant number of practitioners certified to perform and interpret CBCs and differentials from in-house analyzers. Over 100 million CBCs are performed each year in U.S. physician offices. CLIA-waived hematology testing includes only basic hemoglobin and hematocrit parameter readings, typically performed on a handheld or small benchtop instrument. The promise of a CLIA-waived test providing hematology differentials and otherwise moderate/high complexity readings was significant enough to prompt the acquisition of one such developer, Swedish POC test leader HemoCue, by Quest Diagnostics and, most recently, Danaher Corporation. HemoCue offers the first portable tests providing white blood cell (WBC) counts and differentials.

Initially targeted as product segment of interest in Kalorama’s upcoming hematology report, HemoCue’s WBC devices have seen little development on the U.S. regulatory front. The company’s WBC System - a portable device providing a total white blood cell (WBC) count - ultimately received classification as a “moderate complexity” test by the U.S. FDA. The company’s subsequent WBC DIFF system has yet to be approved by the FDA, and is unlikely to be waived under CLIA. Waiving differentials under CLIA has proven problematic as even the most sophisticated analyzer commonly requires verification of automated parameters due to instrument error in classifying nucleated cells and variant leukocytes. While contributing to existing POL and POC markets among certified testers, HemoCue’s WBC products are unlikely to see broader use in the U.S. healthcare system typical of CLIA-waived tests.