The Changing Face Of Diagnostic Testing

Manufacturers make their cases for both in-clinic and referral testing.

In the beginning, there were reference laboratories.

Although turnaround took a while, they could always be counted on to provide accurate results.

Today the diagnostic testing landscape has changed. Large reference labs such as Antech (Irvine, Calif.) and Idexx (Westbrook, Maine) still ply their trade, but the rise of in-house test kits and analyzers has introduced new testing alternatives to the veterinary industry.

Idexx now provides clinic-based hardware as well as sendout services, and Antech has opted to remain with its traditional reference offerings.

With the expansion of testing options, is the handwriting on the wall for the end of reference laboratories?

Not at all, said Darin Nelson, Antech's senior vice president. "We have much higher-end, more expensive equipment than practitioners have in their clinics," Nelson said. "You get much more information, many more analyses and checks for more abnormalities than in-office analyzers or test kits can provide.

"It's like comparing a Lamborghini to a Kia," Nelson said. "Many of the in-clinic hematology analyzers use an older technology called impedance that has problems with the small red blood cells that animals have, especially in differentiating them from platelets, such as the larger ones seen in cats."

Nevertheless, Idexx has opted to cover both bases, bringing to market a number of in-house testing products including its VetTest Chemistry Analyzer, VetLyte Electrolyte Analyzer and the LaserCyte Hematology Analyzer.

Catching Renal Problems Early
Heska's new E.R.D. (Early Renal Damage) test kit is a urine test device designed to spot early signs of renal damage while it is still treatable.

"These tests detect microalbuminuria, or small amounts of albumin in the urine," said Todd Gilson, the company's marketing manager for E.R.D. health screens.

The benefits are two-fold: In a known sick animal, it allows you to better manage the patient by keeping track of the progression of the disease. In a clinically normal animal, the presence of microalbuminuria is a signal to the veterinarian that he or she needs to look more closely at the patient.

"Most veterinarians who have been successful with this test offer it to their clients as part of a standard exam," said Gilson. The more clients view the test as a normal part of checking their pets' health, the more likely they are to accept the test, and staff can play a key role by educating them about why it's needed. The bottom line is that many veterinarians are now finding diseases using the ERD that would have otherwise gone undiagnosed. Animals are being treated earlier and are living happier lives as a result."

Darin Nelson, Antech's senior vice president, said Antech is gearing up to offer the E.R.D. as part of its wellness program on a reference lab basis. Veterinarians who do the test in-house and receive a positive result can send a sample to Antech for confirmation.

Idexx is currently developing a new chemistry application designed to run on its VetTest analyzer that will screen for renal problems using a urine protein creatinine ratio. "It's a much more specific indicator of early renal disease, and we'll be launching it later this summer," said Brad Brazell, the company's senior marketing manager for hematology. —M.C. 

"The LaserCyte uses laser-flow cytometry, the technology used in the major reference laboratories," said Brad Brazell, the company's senior marketing manager for hematology.

"The analyzer can identify different types of blood cells that would not be identified by basic laboratory equipment. It's the first laser-flow cytometry system that can be put to use in a clinic in a cost-effective way."

"Oxford Science, in Oxford, Conn., has introduced its ForCyte analyzer, the first in-clinic device to use both impedance and laser technology to produce a hemogram. Company president Ed Carver said "Impedance is good at counting and sizing, so it tells you how many blood cells are there and how big they are, but it's not very good at differentiating what's inside the cell.

"Laser is very good at seeing what's inside the cell, but not very good at counting and sizing. The marriage of those two technologies is what gives you the accuracy."

Other in-clinic testing systems include The Analyst, which Jim Miller, general manager of Hemagen's clinical chemistry analyzer systems division described as a semi-automated unit, and Abaxis' VetScan chemistry and hematology analyzers.

Pat Conboy director of marketing for veterinary medicine at Unions City, Calif.-based Abaxis noted that the VetScan biochemistry unit is a completely portable automated system originally designed for a NASA spacelab.

According to Conboy, the VetScan unit features a disposable single-use rotor that provides a high level of quality control.

Heska (Fort Collins, Colo.) has introduced its new CBC-Diff veterinary hematology system, which, according to the company, can produce an automatic hemogram in less than a minute. The unit joins Heska's SpotChem EZ Analyzer and the i-Stat Portable Clinical Analyzer in the company's stable of products.

If in-house analyzers are as accurate and easy to use as their manufacturers say, why do veterinarians continue to use reference laboratories? Antech's Nelson noted that his labs serve 17,000 hospitals nationwide, averaging around 20,000 tests per day in the hematology category alone.

He said tests such as chemistry panels are still less expensive to outsource than to run in-clinic. And, it's hard to put a price on the expertise his company's medical professionals bring to the table Nelson said.

"The one thing a chemical analyzer will never come with is a clinical pathologist with a white lab coat," Brazell agreed. "That's why one of the tenets of our strategy is to maintain both high-quality reference lab services and in-clinic equipment.

"Idexx believes in a balance between reference lab work and in-clinic instruments. Veterinarians know that there are reasons to do some tests in-clinic and reasons to send some out."

In-clinic systems become vital when time is of the essence, Miller said. "For emergency cases, it almost has to be done in-house. If a veterinarian has a sick animal in front of him, he can draw the blood sample and have his results in less than 15 minutes."

Carver agreed, likening many clinics to MASH units. "With patients coming in that are really sick, the veterinarian can't always wait to send a sample out," Carver said. "The results can take from eight to 24 hours to return from a reference laboratory. If he didn't have in-clinic instruments, he'd have to guess at a diagnosis."

But how accurate are in-house systems? Nelson maintained that quality control is often lacking with in-house equipment, leading to inaccurate results. "If you do 10 CBCs a day and you do a control once a month, what happens when you discover a problem? Maybe you've done 250 CBCs by then, and you have no idea when the machine began to malfunction."

At Antech, quality control samples are run multiple times a day, Nelson said. "If a veterinarian doesn't run a control sample on a daily basis, or multiple times a day, her instrument may not be giving her the correct answer."

Carter said his analyzers don't need as much intensive care. Carver prefers another analogy to Nelson's Lamborghini/Kia. "I'd say it's like comparing a Formula One race car to a Honda Civic," he said. "The F1 engine revs at 14,000 rpm and after 500 miles will need to be rebuilt, but it's checked continuously during a race.

"The Honda revs at 6,000 rpm, but it can go for 50,000 to 100,000 miles without even a tune-up. Our system is like the Honda-it doesn't see nearly the wear and tear that the reference labs' do."

Regarding VetScan, Conboy cited the integrated quality control of its disposable rotor: "This QC checks both the analyte performance as well as the optical performance of the instrument. Bar-code calibration is included with each rotor. We include extensive QC with every sample run."

Once-a-month controls are simply inadequate, said Fred Mitchell, Heska's marketing manager for instrumentation. "While a monthly QC may have been acceptable five years ago, it isn't now," Mitchell said. "Refusing to acknowledge the need for more frequent quality control is a head-in-the-sand mentality; performing regular QC is simply the right thing to do."

One area in which reference laboratories have an advantage is in pricing. While hematology analyzers can now produce a CBC at a cost that rivals the big labs, the same is not yet true for chemistry profiles and other tests.

"Reference lab testing will almost always be less expensive than in-clinic testing on a cost per test basis," Mitchell said. "Some esoteric tests should always be run in a reference lab. For most clinics, however, there is a happy medium between those tests that can be cost-effectively run in the clinic and esoteric tests that can be run at a reference lab."

An advantage inherent with in-house systems is that they eventually pay for themselves, advocates said. Many practitioners opt for a three- or four-year lease, at the end of which they own the equipment.

"More than half our instruments are leased by veterinarians, since the LaserCyte costs close to $20,000," Brazell said. "But the lease agreement is about $400 per month. The typical cost of a CBC to the client is around $30, and most of our veterinarians average about 15 CBCs per week, so it's not a stretch for them to pay for the instrument very easily based on the volume they do."

Craig Tockman, DVM, owner of Veterinary Care Center in St. Louis, Mo., leases Abaxis equipment and uses it almost exclusively instead of reference laboratories. "We'll send off CBCs occasionally if we get a really strange one with a high white cell count or if we desperately need something like a reticulocyte count," Dr. Tockman said. "But most of the time it's done here, and we find the results to be extremely accurate."

At the other end of the scale is Jeff Werber, DVM, owner of Century Veterinary Group in Los Angeles, who prefers to submit most of his test samples to a reference laboratory.

"Would I ever make a major diagnosis based on the results from a test kit? No way. And I wouldn't trust an in-house analyzer as much as I do the reference lab equipment," Dr. Werber said, mentioning the specter of litigation in the event of an equipment malfunction.

"The reference laboratories give me more tests and more accuracy, and more peace of mind from a legal standpoint," Werber said.

Practitioners such as Werber are one reason reference laboratories will continue to coexist with in-house diagnostic equipment and test kits for the foreseeable future, whether they serve as a primary testing resource or a place to confirm a diagnosis for veterinarians who rely on in-house analyzers.

"In-clinic testing is a must for screening and emergencies. The reference laboratory is a must for certain abnormal conditions and extended or exotic tests," Carver said.

"There is a time and a place for both." 

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