The Shocking Truth About Lab Tests: Part 1

The Shocking Truth About Lab Tests: Part 1Medicine is always changing, and in many ways, that’s a good thing. While many diagnoses can be made by asking a few questions and performing a thorough physical exam, ordering laboratory and imaging tests is a crucial part of modern medicine. These tests allow us to catch previously fatal diseases early, to choose appropriate treatments, and to help families know what to expect. Those sound like great things–and in many cases, they are.

If our tests were perfect (and free) there would be little reason for concern. But nothing in life is perfect (or free), so sometimes things get complicated. Especially because — when ordered or interpreted inappropriately — tests can result in expensive bills, unnecessary procedures, confused patients, and even more confused doctors. The fact that we can order a test doesn’t mean that we should. So while parents don’t typically decide which tests to order, it’s useful for them to understand a few important limitations:
  • Sometimes, there’s no test. Despite some pretty amazing medical advances, we can’t always live up to our patients’ expectations. Parents often want information about their child’s current condition or future prognosis that we just can’t provide until we’re looking back years later. Heck, we can’t even predict what color their eyes will be.
  • Tests require interpretation. When lab results come back, they usually don’t provide a complete picture. For instance, a low hemoglobin level could be a sign of a nutritional deficiency, a red blood cell disorder, GI bleeding, cancer, heavy menstrual periods, or a number of other problems. Test results are like puzzle pieces; they require someone to put the information together using a knowledge of what the values mean, the disease processes that can affect them, and–most importantly–the patient that donated the sample.
  • Context is everything. Even tests that we think of as being a simple yes/no answer can require some thought. A positive pregnancy test in a sexually-active 18-year-old is very different from the same result in a post-menopausal woman. Or from a man, for that matter — when tests are used inappropriately, the answers they provide may not mean what you think they do.
  • “Normal” isn’t always normal. This comes up a lot in pediatrics. The laboratory values we expect to see in a newborn are frequently different from the expected values for adults. For example, a bilirubin level of 14 in a 5-day-old infant is expected. In an older child or adult (or a 1-day-old infant), it should raise some serious concerns. There are plenty of cases where–for a particular patient — an “abnormal” value is what we should expect… or where a “normal” value should be very concerning.
  • No test is perfect. In fact, some of them are pretty much useless. But even good tests will sometimes provide inaccurate results. Some tests tend to have more false positive results (positive tests without true disease); others tend to err on the side of false negatives (missing an actual problem). I could drone on for hours about statistics, but here’s the main point: every test has unique properties that guide when we should use it and how we should interpret the result, and these properties are almost as important as the result itself.
  • Tests cost money. Lots of money. Estimates vary, but those who know healthcare will tell you we waste billions of dollars every year on unnecessary tests. A rapid strep test or chest x-ray may not seem like a big deal, but the costs multiply quickly when you look at a whole population. Many tests are also potentially harmful, requiring the use of radiation, contrast, or invasive procedures. And often, a single abnormal result leads to a long, expensive, and confusing search for increasingly rare diagnoses — just to find that the only problem was the lab result.
  • Tests often lead to treatments. Abnormal laboratory values frequently lead to treatments — after all, that’s usually why we ordered them. These treatments may save someone’s life, provide relief from symptoms, or improve someone’s quality of life. But sometimes test results lead to unnecessary treatment for a “problem” that never existed or that would have gone away on its own. And just like tests, treatments aren’t perfect; every treatment carries some level of risk, so ensuring that we test and treat only when we should is part of practicing conscientious medicine.
To be honest, often the answer really doesn’t even matter. We have the ability to run a test from a nasal swab that can identify about a dozen of the most common respiratory viruses. In certain circumstances, it’s a very useful test. However, it’s also very expensive. And while some parents would love to know the exact name of the virus causing their child’s runny nose, it usually wouldn’t change the child’s course of treatment at all. In short: Unless the answer might actually matter, the question probably isn’t worth asking.

If you have questions or concerns about your child’s health or want to schedule an appointment, don’t hesitate to give MacKoul Pediatrics Cape Coral a call at 239-573-2001.

And be sure to check out The Shocking Truth About Lab Tests: Part 2!

About author MacKoul Pediatrics

MacKoul Pediatrics is an amazing local pediatrics office in Cape Coral, FL where caring, compassionate doctors and nurses work with you to keep your children as healthy as possible. MacKoul cares for children from birth to college age, from Cape Coral, Fort Myers, Naples, and beyond.
July 19, 2016