Why did my lab print two columns of previous results?
Labs print previous results in extra columns so you can see how a value has changed over time. The trend, or direction of travel, often tells you more than a single reading [CLSI, 2010]. Each column is usually dated, with the most recent result first.
Last reviewed: 2026-08-16
What are the extra columns showing?
Each extra column is your result for the same test on an earlier date. The dates are printed at the top of the columns.
Reading across a row shows how one test has moved between visits.
Why is the trend useful?
A steady value, a rising value and a falling value can mean very different things. The trend adds meaning a single number cannot [CLSI, 2010].
Labs sometimes run a delta check, which flags a surprisingly large change between visits.
How should I read the trend?
Look at the direction and the size of the change, not just the latest number.
Bring the dated columns to your doctor, who reads the trend with your history and any change in treatment.
Frequently asked questions
- Which column is my latest result?
- Usually the first result column, next to the reference range. Check the dates at the top to be sure.
- Is a small change between visits important?
- Often not. Values move a little naturally. A clear direction over several tests usually matters more than one small step.
- What is a delta check?
- A delta check flags a large change from your previous result, prompting the lab to confirm the value before it is reported [CLSI, 2010].
- Can I compare columns from different labs?
- Take care: different labs use different methods and ranges, so a trend is cleanest when the results come from the same lab.
Sources
- CLSI (2010) — Clinical and Laboratory Standards Institute (reference intervals, methods, specimen handling)
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