How to Combine Lab Results From Different Labs Into One Timeline

If you've had blood drawn at more than one place — a Quest lab this year, a LabCorp draw two years ago, a Function panel in between, a hospital test somewhere in there — you don't have one lab history. You have four, in four formats, each sitting in its own portal — because each lab keeps only the results it produced.¹ The single most useful question you could ask of that data — how has this marker moved over time? — is exactly the one a stack of disconnected reports can't answer.

Pulling those results onto one timeline sounds like it should be a copy-paste job. It isn't, and the reasons are worth understanding before you try. This guide covers why it's hard, how to do it manually, and how to make it stop being a chore.

Why this is harder than it looks

Every lab measures the same biology, but each one reports it differently. Three mismatches make a simple merge fail.

Different units. The same marker can be reported on different scales. Total cholesterol of 5.0 is alarming in mg/dL and completely ordinary in mmol/L — same substance, a factor of roughly 39 between them.² Glucose, vitamin D, and triglycerides all have this problem. Stack two results without converting, and you're comparing numbers that were never on the same axis.

Different reference ranges. A reference range is not a fixed definition of "healthy" — it's the band a particular lab considers typical, and because labs use different testing methods, they set different ranges.³ A value flagged high at one lab can sit comfortably in range at another. That's also why MedlinePlus advises using the same lab when you're looking for trends: it keeps the ruler constant.³ When you can't use the same lab, you have to carry each result's own range alongside it, or a chart will mislead you.

Different names and formats. One lab calls it Vitamin D, 25-OH; another writes 25-hydroxyvitamin D. Panels are grouped differently, dates are formatted differently, and it all arrives as a PDF laid out for a human to read once — not as data built to be combined. Before you can chart anything, you have to recognize that three differently-labeled rows are the same marker.

None of this is exotic. It's just enough friction that most people give up and leave the results where they landed.

Get every result into your hands first

You can't combine what you can't reach. Each lab holds its own copy of your results, and you have a right to a copy of all of them.⁴ So step one is collection:

• Quest results live in MyQuest; LabCorp in the LabCorp Patient portal — our guide to exporting Quest and LabCorp results walks through downloading each as a PDF.
• Function Health and other membership panels have their own dashboards and exports; here's what to do with Function results when you want to keep them.
• Hospital and clinic labs usually surface in a provider portal like MyChart.

If a result isn't in a portal, you can request it directly from the provider — the mechanics are in our guide to getting your medical records. The goal at this stage is simply: one copy of everything, gathered in one place.

The manual approach (and its ceiling)

Once you've gathered the PDFs, the do-it-yourself method is a spreadsheet:

1. One row per marker, one column per date. Pick a marker — say ApoB or HbA1c — and enter each result under its draw date.
2. Normalize the units. Convert everything for a given marker to a single unit before you type it in, so mg/dL and mmol/L values don't share a cell as if they were equal.
3. Reconcile the names. Decide that Vitamin D, 25-OH and 25-hydroxyvitamin D are one row, not two.
4. Keep each result's reference range. Note the range printed on that report next to the value, since ranges differ by lab.
5. Repeat for every marker you care about.

This genuinely works, and for a handful of markers it's fine. Its ceiling is labor: it's slow, it's easy to get a conversion wrong, and it decays the moment a new PDF arrives and you don't feel like updating the sheet. The markers glossary can help you match names, but the transcription is still on you.

How Libby automates it

The reconciliation problem is mechanical, which means software can do it. This is the specific job Libby is built for. You import the PDF — or snap a photo of a paper result — and Libby:

• Reads every value off the report, so there's no re-typing.
• Reconciles the units across labs, so a mmol/L result and a mg/dL result for the same marker land on the same axis.
• Matches marker names across Quest, LabCorp, Function, and hospital systems on Epic or Cerner, so differently-labeled rows collapse into one.
• Stacks each marker on one timeline, carrying each result's own reference range, so a 2019 result sits next to a 2026 one and the trend finally becomes visible.

The result is the thing the spreadsheet was reaching for, without the transcription: a personal health record that spans every lab you've used, that you own and can export anytime, and that you can hand to a doctor or an AI assistant when you want a second read.

If your labs are scattered across a couple of portals right now, start your record and drop the first PDF in — the first import takes about a minute, and each one after that just extends the same timeline.

FAQ

Why can't I just put results from different labs in one chart? Because they're often not on the same scale. The same marker can be reported in different units (like mg/dL vs. mmol/L), labeled with different names, and measured against different reference ranges. You have to convert units, match names, and carry each report's own range before a combined chart means anything.

Why do reference ranges differ between labs? Labs use different testing methods and equipment, so they calibrate to different reference ranges. A value flagged high at one lab can be in range at another — which is why it's best to read each value against the range printed on that report, and to use the same lab when you're tracking a trend over time.

Can I combine Quest and LabCorp results? Yes. Export the PDFs from MyQuest and the LabCorp Patient portal, then import both into a single record that reconciles units and marker names across labs, so every result lands on one timeline instead of staying in two separate portals.

Do I need to convert units myself? If you do it manually, yes — you have to convert each marker to a single unit before comparing. Libby does this reconciliation automatically when you import a PDF or a photo of a result, so results from different labs line up without hand-conversion.

What about a photo of a paper lab result? You can import a photo, not just a PDF. That covers older results and anything you only have on paper, so the whole history — not just what's still in a portal — ends up on one timeline.

Educational content, not medical advice. This article is for general information and personal record-keeping. It isn't a diagnosis or a treatment plan, and reference ranges vary by lab and by person. Always talk to a qualified healthcare professional about your results and any decisions that follow from them.