How to Use & Interpret Blood Tests for High Performance

Reference Ranges

Understanding reference ranges is crucial for interpreting blood test results accurately. Andy Galpin explains that these ranges typically use the 95% rule, meaning 95% of people fall within a specified range, like 300 to 900 for testosterone 1. However, this doesn't account for performance needs, where being at the 10th or 90th percentile can make a significant difference. He also highlights the variability in free testosterone calculations due to different lab equations, emphasizing the need for consistency in lab choices 2.

Someone who's at the 10th percentile, who's trying to perform at their best, is not at the same level as someone who's at the 90th percentile, both within the normal, quote unquote reference range.

--- Andy Galpin

This underscores the importance of understanding how these ranges apply to individual performance goals.

   

Marker Variability

Blood marker variability is another critical factor in interpreting test results. Andy discusses how some markers can vary by up to 5% due to analytical limitations, diurnal variations, and biological factors 3. For instance, creatinine levels can be misleadingly high in athletes due to muscle mass and creatine intake, often causing unnecessary concern about kidney health 4.

If you're going and interpreting your blood draw this time compared to your last one or the previous one, and your marker has changed by less than 5%, it's probably not a real change.

--- Andy Galpin

Understanding these variabilities helps in making more accurate assessments and avoiding false alarms.

   

Contextual Analysis

Contextual analysis is essential for making sense of blood test results. Andy emphasizes that the interpretation of markers like hemoglobin and hematocrit should vary based on the individual's performance goals, such as endurance versus strength training 5. He also notes that markers important for long-term health, like APOB, may not be as relevant for high-performance athletes 6.

The primary difference between blood work for performance and blood work for health or disease is not just in the markers. It's mostly in the interpretation, the context and the evaluation of the results.

--- Andy Galpin

This approach ensures that blood test results are used effectively to enhance performance and health.