The Mystique of Laboratory Testing

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The Mystique of Laboratory Testing

There is a mystique surrounding laboratory testing. The vast majority of us believe the values we get for any single test sample (blood, urine, saliva, whatever) represent our health status. On the one hand this is truthful, especially when it comes to the most important minerals in our body; sodium , potassium, carbon dioxide, acidity, and so on. Those values fluctuate in relatively narrow ranges and we are very ill – or dead – when our levels fall outside those ranges. These numbers have been vital to health care for as long as we knew how to collect samples and test for specific substances.

A key to a broader understanding shortcomings of laboratory testing is that we usually test a sample and receive a snapshot of how things were at that precise moment. For elements that vary little (electrolytes, minerals, pH), this is good. However, there are a myriad of substances in the human body that change daily, hour-by-hour, or even every minute. In these cases it is all but futile to accept the results of a single moment in time and apply some sort of therapeutic treatment. It would be legitimate if the snapshot represented the truth of our measured values day after day and minute after minute, but they don’t.

I attended a health seminar several years ago, right around the time when cholesterol testing was just beginning to be popular (when statin drugs were gaining in popularity). There was a sales booth set up that was promoting cholesterol testing equipment. I had my cholesterol tested three times in two days and the results were wildly different and not easily associated with what I had been doing or eating. One was “low” and two were “high” – relative to the normal values at that time. I asked the doctor at the booth which level I should use. He didn’t know. That’s when I got my first indication that the entire cholesterol “thing” might be based more on selling tests and drugs than on keeping me healthy. But, that’s another story. The point here is to demonstrate how cholesterol levels derived from a single blood test couldn’t be trusted. In this case, I would have been prescribed a drug based on two of the results, and informed that I was “fine” based on the third – all based on three blood samples collected over a 24 hour period.

Cholesterol levels vary because our bodies need varying amounts to meet specific needs throughout the day. A snapshot test might reflect an average, but it is also likely it reflects the level during a moment when our general level is on the rise – or decline. A better indicator would be a series of tests over time accompanied by a search for a pattern. Cholesterol is part of the hormone system – the basic “starter material” for all hormones. By definition, a hormone is a substances that changes to meet specific needs at varying times. It isn’t a stable value.

Hormones? Like cholesterol, hormones rise and fall to meet our needs. As with all testing, the data for hormone levels are derived from a mathematical manipulation of data created by millions of tests over many years. The same variations that impact cholesterol alter the way our hormone tests are displayed.

I’m often asked about a specific hormone results, “my blood test showed that my testosterone is low normal”. They want to know what I’d suggest as a hormone replacement treatment. When it’s my turn to respond I ask if they know what their level was when they were, for example, when they were 21 years old. Nobody has been able to offer historic test values other than the ones they just received.

One thing to note is that the vast majority of the millions of values in the data banks are derived from hospitals and clinics, places where sick people are tested. Over time, the large numbers tested create a base of values that approach a normal distribution for most people. Sometimes the labs break out data by gender, and even by age. The fact remains, though, that every test is merely a value for that particular moment in time, and might not actually relate to an overall health situation.

What’s a person to do when they’re tested during routine doctor visits? First, understand that the values might equally be correct or wrong, especially if testing substances that are fat soluble (cholesterol, hormones, and so on). Be careful about attributing too much weight to the results, especially when the commentary suggests the results are at the low or high end of normal. Normal is still normal and being in the range is okay.

Consider doing your own testing and documenting. While it is common for tests to be ordered by a doctor, it is not absolutely necessary. There are lab services with several local drawing sites that will collect your sample and send it for testing. The costs are nominal (aka, affordable and usually far less than when ordered by a doctor and paid for with insurance) and the customer can take a look at their results over time and evaluate them according to how they are feeling. One such lab service is ULTA LAB TESTS. They offer a Cardio IQ Panel that provides a comprehensive lipid analysis, which measures cholesterol concentrations of all 5 lipoprotein classes and their sub-classes. The list price for the complete panel is $93.00 (August, 2018).

2018-08-28T18:15:53+00:00August 28th, 2018|Blog|