Associated Veterinary Specialists - Advanced Veterinary Care - St. Louis, MO
AVS Veterinary News

In-House Laboratory Equipment: An Editorial

I have been in the position of receiving referred cases for 30 years now. One of the most disturbing trends I have witnessed in veterinary medicine is the frequent use of laboratory equipment in veterinary clinics. You may not be aware that in 1988, the Congress passed a law called the Clinical Laboratory Improvement Act (CLIA) that regulated the use of laboratory equipment in physicians’ offices. Essentially it said that this could only be done with the same standards of quality control that are required for reference laboratories. Why did this happen? Because the results were often inaccurate. As you know, inaccurate laboratory values directly lead to errors in diagnosis and therefore treatment. Now, I realize that some STAT laboratory values must be used when reference laboratories are not available. That, however, does not absolve the clinic performing these tests from instituting a program of rigid quality control that is supervised by professionals in laboratory medicine. Bad results in the middle of the night are just as damaging as bad results during the workweek. I believe that it is incumbent on anyone that does their own labwork to make sure that quality control is used and laboratory professionals perform the work. Veterinary technicians that have multiple other responsibilities should not be depended upon to provide the quality of laboratory results that we all require. Medical Technology is a rigorous 4 year college degree program that prepares people for a career in laboratory technology. Should our results be produced by people that are not qualified to do this work? Many of the referrals that come to me have accompanying in-house laboratory results. How many of the CBCs have an accompanying differential that has been performed by a qualified person – none. Some high quality hematology machines will provide a differential but, they must be constantly monitored by qualified personnel. Specific guidelines are used to decide when slides should be reviewed. I have found in my own experience that calciums, bilirubins and albumins are frequently erroneous. I have seen BUNs 50% different than a reference value! In fairness, I have also seen that the ALT and ALP values are fairly accurate but, only when they are within certain ranges. I recently had a referral where two ALPs were “Can’t Measure”. The reference laboratory value for ALP was 2582 IU/L for this pet. The client paid for but did not receive any value for this test. In-house instruments are designed to be accurate when the test result is within the normal range but have limited ability to provide accurate results when they lie outside the normal range. Many of the in-house T4s will only record a number up to a certain value but, I need an accurate number to formulate an I-131 dose. A 12 year old cat was referred for persistent vomiting thought to be caused by hyperthyroidism. The cat had been treated for 2 years with methimazole. The original diagnosis was based on an in house T4 value about 20 % above the reference range and a small thyroid nodule. We elected to discontinue methimazole and reevaluate the T4 in a week. At that time the T4 was in the low part of the normal range. Subsequent evaluation revealed lymphoplasmacytic enteritis! Most in-house chemistry profiles are incomplete where many important parameters are missing. Triglycerides and CPK values are not included in in-house chemistry profiles and are very important in some cases. One of the most difficult problems with in-house laboratory results is that they are often incomplete and untrustworthy. That causes me as the referral clinician to have to inform the client (as diplomatically as I can) that I need more tests to be performed to evaluate the case. If a fair amount of time has elapsed since the first blood work was done, it is easy to request a reevaluation. If the work was done within a few days, clients often question why it has to be done again. That puts me in a position where I have to inform them why I need more tests when they just paid for the tests. This is a very uncomfortable position for me where I wish to maintain the client’s confidence in their family veterinarian but in order to adequately treat the pet I must confirm the laboratory findings. The financial aspect of these instruments is not my concern. I do however suspect that they cost a lot more than their salespeople will tell you. I recommend that you seriously evaluate the pros and cons of these instruments before you buy. In my opinion they are not what they are purported to be. Do they upgrade the quality of medicine or the client service that you perform as I have seen advertised? Without proper quality control and trained laboratory personnel, my answer would be a categorical NO. I have several specific recommendations: 1) When doing routine screening bloodwork when time is not an issue, send the samples to a reference laboratory. 2) When in house labwork is done such as for a preop screen and any value outside the reference range is found, rerun the sample at a reference laboratory. 3) A CBC must be accompanied by a differential so if a qualified technician is not available to perform the differential, send the sample to a reference lab. 4) When a laboratory abnormality is found (such as elevated ALT), monitoring should be done by a reference laboratory.