The Truth behind Lab Values

When you visit a healthcare provider for a routine check-up or when you're feeling under the weather, one common practice is to undergo blood work. These tests provide valuable insights into your overall health and help doctors diagnose various conditions. But have you ever wondered how medical professionals establish the normal ranges for these lab values? Surprisingly, one of the methods they use involves averaging data from sick individuals. In this blog post, we'll delve into the science behind this approach and explore how it contributes to modern medicine.

Understanding Lab Values

Before we dive into how lab values are established, let's briefly discuss what they are. Lab values are numerical ranges that indicate the normal levels of various substances in your blood. These substances can include white blood cells, red blood cells, platelets, electrolytes, hormones, and more. These values are used as reference points to evaluate your health and diagnose potential issues.

The Challenge: Variability in Health

Human bodies are incredibly complex, and no two individuals are exactly alike. Factors such as age, sex, genetics, and lifestyle can lead to variations in blood composition. Moreover, diseases and medical conditions can significantly alter blood test results. This inherent variability poses a challenge when establishing universal reference ranges.

Averaging Sick Individuals?

While the idea of using data from sick individuals might seem counterintuitive, it has a logical basis. When someone is ill, their blood values can deviate from the normal range. By gathering data from a diverse group of sick patients, medical researchers can gain insights into how lab values shift during various illnesses.

The Role of Statistical Analysis

Statistical analysis plays a crucial role in making sense of the data collected from sick patients. Researchers gather a large pool of blood test results from individuals diagnosed with specific conditions. They then calculate the average and standard deviation of these values. The average provides a central point of reference, while the standard deviation indicates the extent of variability.

Standard "normal" ranges for tests with numeric values are based upon use of a bell shaped curve. "Normal" is usually defined as those test values that fall within 2 standard deviations of the mean, which includes 95% of all results. The standard deviation is just a measure of dispersion.

Establishing Reference Ranges

After collecting and analyzing data from a broad range of patients, including those who are sick, researchers work to establish reference ranges for various lab values. These ranges typically encompass the average value plus or minus a certain number of standard deviations. For instance, a common reference range might be "normal" if your blood value falls within the average value ± 2 standard deviations.

Benefits of Using Sick Patient Data

  1. Comprehensive Understanding: Including data from sick individuals allows researchers to create more comprehensive reference ranges that account for variations caused by diseases.

  2. Diagnosis Accuracy: Doctors can better diagnose and monitor patients by comparing their blood test results against reference ranges that consider the effects of illnesses.

  3. Early Detection: Some medical conditions might manifest as subtle changes in blood values before other symptoms appear. Averaging data from sick patients aids in detecting these early indicators.


The practice of using data from sick individuals to establish lab values might seem paradoxical at first glance. However, it's a crucial approach that helps medical professionals create more accurate and versatile reference ranges for blood work. This method takes into account the natural variations in health and provides doctors with a better understanding of how various diseases can impact blood test results.

As a Functional Medicine Physician Dr. Leasure utilizes Optimal Ranges...ranges that are associated with better future health and higher life expectancy. We're looking to help your body function at an optimal level, not merely avoid being sick or developing a disease. If you're looking for a more thorough analysis of your blood work; to determine how far your values are from optimal you'll want to grab our Functional Blood Chemistry Analysis. A detailed report of how far your results are from Optimal, see how your lifestyle modifications are improving your health in real time and see which diseases you may be on the trajectory to developing or preventing!


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