Guide · Reading results

Optimal vs reference ranges: what’s the difference?

On this page
The short answer

A reference range is the laboratory’s range for the middle 95% of a healthy reference group. It tells you whether a result is unusual. An optimal range is a narrower target linked to better health outcomes in published research. Vively shows both side by side and never replaces the lab’s range.

How labs set reference ranges

Most reference ranges cover the middle 95% of results from a group of healthy people. By design, about 1 in 20 healthy people fall outside the range for any single test. Australian labs share harmonised ranges for many common tests, and each report shows the range the lab used.

A result inside the reference range is common in that population. That isn’t the same as ideal for your client.

Interactive

Where do 20 healthy people’s results land?

Outside the lab range (about 1 in 20)Lab reference range: middle 95%Vively optimal range

Press Sample 20 people to drop 20 results from a healthy reference group onto the curve.

“The lab range answers one question: is this result unusual? It’s an important question. It just isn’t the only one.”

Dr Michelle WoolhouseFounding Medical Director, Vively

What an optimal range adds

An optimal range narrows the target to where published studies link results with better outcomes. It helps you spot a trend early, like fasting insulin creeping up while glucose still looks normal, and gives your client a clear goal.

When every result looks normal

Picture a client Dr Woolhouse sees all the time. She’s in her late forties, tired, sleeping badly, and her weight has crept up over a few years. Her bloods come back and every result is inside the lab range. On paper, she’s fine. Switch between the two views to see what the optimal range adds.

Illustrative client · not a real person

Six results from one blood test

  • TSH3.4 mIU/LLab 0.5–4In range
  • HbA1c5.6 %Lab 4–5.7In range
  • Triglycerides1.8 mmol/LLab 0.5–2.1In range
  • Vitamin D132 nmol/LLab 50–200In range
  • Ferritin96 µg/LLab 15–400In range
  • ALT16 U/LLab 5–35In range

Laboratory view: 6 of 6 results in range. Nothing is flagged.

None of that is a diagnosis. Together, though, the three Normal results show where she may be heading, and they give the two of you something specific to work on now: thyroid function, blood glucose and blood fats.

Examples from the Baseline

MarkerTypical lab rangeVively optimal range
Fasting insulin3–10 mIU/L3–5 mIU/L
HbA1c4.0–5.7 %4.0–5.3 %
Vitamin D50–200 nmol/L120–200 nmol/L
TSH0.5–4.0 mIU/L1.0–2.5 mIU/L
Triglycerides0.5–2.1 mmol/L0.5–1.2 mmol/L
LDL cholesterol1.7–3.5 mmol/L1.5–2.6 mmol/L

Lab ranges vary by laboratory, age and sex. The platform always shows the range on your client’s own report.

Interactive

Range explorer

Pick a marker, then move the result to see how the laboratory and Vively views read it.

Metabolic health
5.5 %
Laboratory view
In range
Vively view
Normal

Drag the marker along the bar, or use the arrow keys.

Laboratory range 4–5.7 %Vively optimal 4–5.3 %

What it measures

Average blood glucose over the previous two to three months. Glucose attaches to haemoglobin in red blood cells, and more glucose means more attaches.

Why the optimal range is narrower

A result such as 5.5% won’t be flagged by the laboratory, but it shows glucose has been running higher than it needs to. That pattern is closely linked with insulin resistance.

Read it alongside

  • Fasting insulin
  • HOMA-IR
  • Iron studies

Keep in mind

HbA1c rises slightly with age, and iron-deficiency anaemia can make it read falsely high.

Ranges shown are Vively’s current ranges. Laboratory ranges vary between laboratories; in Vively every result shows the reporting laboratory’s own range.

How Vively sets and shows optimal ranges

  • 96 markers have a Vively optimal range backed by published evidence
  • Each range lists its sources in the platform, so you can check the reasoning
  • Where the evidence isn’t strong enough, we show the lab’s range only
  • Set your own target for any marker
  • The framework was developed under the clinical leadership of Dr Michelle Woolhouse

“If the evidence wasn’t there, I didn’t set a range. I’d rather show you nothing than a guess.”

Dr Michelle WoolhouseFounding Medical Director, Vively

Explaining ranges to your client

Start with the lab range: is anything unusual? Then use the optimal range to set a goal. Keep context in view, such as age, pregnancy, medications and recent illness. An optimal range supports your interpretation. It doesn’t diagnose.

Test yourself: Optimal, Normal or Suboptimal?

Four quick results. Choose the status Vively would show for each one.

  1. 1. Fasting insulin 8 mIU/L

    Lab range 3–10 mIU/L · Vively optimal 3–5 mIU/L

  2. 2. Vitamin D 45 nmol/L

    Lab range 50–200 nmol/L · Vively optimal 120–200 nmol/L

  3. 3. Ferritin 140 µg/L

    Lab range 15–400 µg/L · Vively optimal 70–200 µg/L

  4. 4. HOMA-IR 2.4

    Lab range 1–2.9 · Vively optimal ≤ 1

“An optimal range supports your interpretation. It doesn’t make the diagnosis for you.”

Dr Michelle WoolhouseFounding Medical Director, Vively

Sources

  1. AACB and RCPA: an update report on the harmonisation of adult reference intervals in Australasia (Clinical Chemistry and Laboratory Medicine, 2018)
  2. Vively marker evidence library (in platform)
Dr Michelle Woolhouse, Vively Founding Medical Director
Dr Michelle WoolhouseFounding Medical Director · Integrative GP · Lifestyle & preventative medicine
Clinical leadership

Optimal ranges you can trust and explain

Dr Michelle Woolhouse, Integrative GP and leader in lifestyle and preventative medicine, led the research behind Vively’s optimal ranges and developed the clinical framework with experienced Australian practitioners.

96 evidence-backed rangesEach Vively optimal range lists its published sources in the platform.
Lab ranges unchangedThe laboratory’s range always shows. The optimal range sits beside it.
Your own targetsSet your own target for any marker, next to the lab and Vively ranges.

See both ranges on every result

Free for practitioners. See both ranges on every result you refer.

  • Free for practitioners
  • No subscription
  • Verified practitioners only