The PAD System

Capillaritis-Acute hemorrhage Michael Weilert MDContinuing improvements in point-of-care testing have been encouraging one major academic medical center to apply the same mode of testing to diagnosing hospital-acquired infections (HAIs).  Since it has the potential to create a different way to identify patients with HAIs, this is of particular interest to clinical laboratory professionals and pathologists.  The Massachusetts General Hospital (MGH) developed a prototype diagnostic system that works with doctors’ smartphones or mobile computers.  According to a statement from the MGH, this hand-held system can identify pathogens responsible for specific HAIs at the point of care within two hours.

An estimated 600,000 patients develop HAIs each year, 10% of which are fatal, and costs related to HAIs can reach $150 million a year.  Yet the Centers for Medicare and Medicaid Services (CMS) does not reimburse hospitals for certain HAIs, therefore the need to identify the infection’s origin becomes critical.  Pathologists and medical laboratory scientists will therefore understand that shifting some of that specimen volume to point-of-care testing will change the overall economics of hospital laboratories.

The MGH research team created an accurate method of genetic testing in a simple device powered by a system called Polarization Anisotropy Diagnostics (PAD), which uses a detection probe to measure changes in fluorescene anisotropy.  There are more than 35 probes available, designed to detect bacterial species and virulence factors.  Optical test cubes are placed on an electronic base station, which transmits data to a smartphone of computer that displays results.  Unlike using a bacterial culture, the PAD assessment works under two hours and is cost-effective (just under $2 per assay).

In a pilot clinical study, researchers used the PAD system to test samples for E. coli, Klebsiella, Acinetobacter, Pseudomonas and Staphylococcus aureus.  They found that PAD and conventional microbiology cultures obtain identical results, yet the PAD system produced the results within two hours (compare that to the 3-5 days necessary for bacterial culturing).  For labs and physicians, PAD can be an additional resource to speed diagnosis, tailor treatment to patients and ensure clean environments.  It’s less expensive than conventional microbiology assays, and offers medical laboratories less risk of cross-contamination of specimens.

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