Getting your lab results can feel overwhelming. Here's how to make sense of those numbers.
Understanding Reference Ranges
Reference ranges (also called normal ranges) are based on where 95% of a "healthy" population falls. But "normal" doesn't always mean "optimal."
Important Points
- Ranges vary between labs
- Ranges are based on population averages
- Being at the edge of normal may still cause symptoms
- Optimal ranges are often narrower
Reading Your Results
Result Columns
- Your value
- Reference range
- Flag (H for high, L for low)
- Units of measurement
Flagged Results
- H (High): Above reference range
- L (Low): Below reference range
- No flag: Within reference range
Common Units
- ng/mL: nanograms per milliliter
- pg/mL: picograms per milliliter
- mIU/mL: milli-international units per milliliter
- mg/dL: milligrams per deciliter
- mcg/dL: micrograms per deciliter
Questions to Ask
- Is this in the optimal range, not just normal?
- How does this compare to my previous results?
- What might be causing abnormal results?
- What should I retest and when?
Tracking Over Time
One result is a snapshot. Tracking trends over time gives you the full picture. Keep copies of all your labs.
References
- Ozarda, Y., et al. (2018). Reference intervals: current status, recent developments and future considerations. Clinical Chemistry and Laboratory Medicine, 56(7), 969-981.
- Ceriotti, F., et al. (2009). Common reference intervals for aspartate aminotransferase (AST), alanine aminotransferase (ALT) and gamma-glutamyl transferase (GGT) in serum: results from an IFCC multicenter study. Clinical Chemistry, 55(3), 549-555.
