How to Read Your Lab Results: A Beginner's Guide

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.