Fasting insulin is a blood test that measures how much insulin the pancreas secretes to hold glucose steady after an overnight fast. Practitioners use it because insulin usually rises years before fasting glucose or HbA1c leave their ranges, which leaves time to act on diet, sleep and exercise. Assays are not standardised, so ranges differ between labs and trends need the same lab.
| Test type | Measured in a blood sample |
|---|---|
| Measurements required | Fasting Insulin only |
| Sample and collection | Fasting blood draw at a collection centre |
| Preparation | Fast for 8 to 12 hours before a morning collection, water only. |
| Turnaround | 3 to 5 business days |
| Available through | Diabetes & Glycaemic Studies, part of the Baseline Health Check. Also in: Full Body Health Check, Metabolic Panel, Female Hormone Health Test, Perimenopause Test, Menopause Test, Fasting Insulin Test. |
| Pricing | Included in the $99 Baseline Health Check |
| Results | Returned in the Vively practitioner platform, beside your client's other markers |
What are the Fasting Insulin reference and optimal ranges?
| Typical lab reference | Vively optimal | |
|---|---|---|
| Adults | 3 to 10 mIU/L | 3 to 5 mIU/L |
Insulin assays are not standardised, so labs quote different ranges; read the result against the range on the client's report (RCPA). The optimal range is a target for early metabolic work, not a diagnostic cut-off.
Check a client's Fasting Insulin result
Enter the value from your client's lab report to see where it sits against the typical lab range and the Vively optimal range.
A guide only, not a diagnosis. One result is a starting point: read it with symptoms, history and a repeat test. Labs differ, so check the result against the range on your client's report. Nothing you enter is stored or sent.
How do you arrange Fasting Insulin testing through Vively?
- Get verified. Practitioners with a recognised qualification or membership (ATMS, NHAA, ANTA, Dietitians Australia, NSA, CMA or Ahpra registration) can request free practitioner access.
- Choose a panel. Log in to the practitioner platform and pick a panel that includes Fasting Insulin, or build your own. It is included in the $99 Baseline Health Check.
- Client collects. Your client collects at a partner collection centre, with their request on their phone or printed.
- Review results. Results come back to you in the practitioner platform, beside your client's other markers, ready for the follow-up consult.
Which Vively panels include Fasting Insulin?
Log in to the practitioner platform to view a panel in full, or build and save your own from 100+ tests and panels.
- Baseline Health Check74 markers across 11 lab groups$99
One fasting blood draw.
Full Blood CountUrea, Electrolytes & CreatinineLiver Function TestsCalcium, Phosphate & MagnesiumLipid StudiesDiabetes & Glycaemic StudiesIron StudiesThyroid Function Tests+3 moreLog in to view this panel - Log in to view this panelMetabolic Panel3 markers · Heart & metabolicPrice on sign-up
- Female Hormone Health Test17 markers · HormonesPrice on sign-up
Two blood tests timed to the cycle, to show how hormones shift across it.
Log in to view this panel
Why does the optimal range sit there?
Our 3 to 5 mIU/L target sits at the low end of the lab range, matching lean, insulin-sensitive adults, because insulin can rise while glucose stays normal.
Lab ranges are drawn from populations where insulin resistance is common, and some Australian labs print an upper limit well above 20 mIU/L. With fasting glucose of 4.5 mmol/L, our target equates to a HOMA-IR of about 1.0.
Vively's clinical view is that 6 to 10 mIU/L with normal glucose is worth acting on. Above 10 mIU/L points more firmly to insulin resistance.
Samaras and colleagues (Medical Journal of Australia, 2006) note there is no agreed insulin cut-off, so we never read insulin alone.
What should Fasting Insulin be read with?
- ContextInsulin above 10 mIU/L, glucose in range
Often seen with early insulin resistance, with the pancreas compensating to keep glucose normal.
- HighRaised insulin, triglycerides 1.7 mmol/L or above, low HDL
A typical insulin resistance lipid pattern; check waist, blood pressure and liver enzymes.
- HighRaised insulin, irregular cycles, raised free testosterone or low SHBG
Possibly an insulin-driven PCOS picture that is worth discussing with the client's GP.
- HighRaised insulin with raised uric acid
Often goes with insulin resistance, as high insulin reduces urate excretion by the kidney.
- LowLow insulin with glucose 7.0 mmol/L or above
Possible reduced pancreatic output and needs prompt GP review.
What can affect a Fasting Insulin result?
- An incomplete fast, including milk or sugar in coffee, which lifts insulin sharply.
- Assay differences between labs; track trends with the same lab.
- Haemolysed samples, which can read falsely low.
- Corticosteroids, some antipsychotics and pregnancy, which raise insulin.
- Very low-carbohydrate diets or prolonged fasting, which can lower fasting insulin without showing how the client handles a mixed diet.
- Insulin therapy, which makes the result uninterpretable.
When should you refer the client to their GP?
- Fasting glucose 7.0 mmol/L or above, or HbA1c 48 mmol/mol or above.
- Low insulin with high glucose, weight loss or marked thirst.
- High insulin with fasting glucose below 3.5 mmol/L, or shakiness, sweating or confusion when fasting.
- Features of PCOS, pregnancy, or a history of gestational diabetes.
How should a client prepare for a Fasting Insulin test?
Copy or print this to send to your client.
Preparing for your Fasting Insulin test
- Fast for 8 to 12 hours before a morning collection, water only.
- Skip exercise on the morning of your test, as it can shift your glucose and insulin.
- Tell your practitioner if you take biotin (often found in hair, skin and nail formulas), as high doses can affect some insulin tests.
- If you take diabetes medicines, check with your GP before you fast.
- Take your pathology request to any of 4,000+ collection centres. Bring it printed or on your phone.
- Keep taking prescribed medicines as usual unless your doctor tells you otherwise.
- Results usually take 3 to 5 business days and come to your practitioner. Book your results appointment for after that.
How do practitioners use Fasting Insulin with clients?
Fasting insulin is often the first metabolic marker to move, so it suits clients who need to see early change. Expect it to respond over months to steady work on diet quality, sleep, stress and exercise, and retest with the same lab after about 12 weeks.
Fasting Insulin FAQs
Can I order fasting insulin for a client as a naturopath, nutritionist or dietitian?
Yes. Add it to a client panel on the Vively practitioner platform. It is part of Diabetes & Glycaemic Studies in the $99 Baseline Health Check, and is also in Full Body Health Check, Metabolic Panel and Female Hormone Health Test. No account yet? Request free access.
Why does Vively's insulin range differ from my client's lab report?
Insulin assays are not standardised, and each lab sets its own range. Some reports print an upper limit above 20 mIU/L, while Vively uses a reference of 3 to 10 mIU/L and an optimal range of 3 to 5 mIU/L. Read the lab flag against the report, then use our ranges with glucose and lipids to judge early metabolic strain.
Should I order fasting insulin with HbA1c?
Yes, for most clients. HbA1c shows average glucose over about three months, and insulin shows how hard the pancreas is working to hold it there. A normal HbA1c with insulin above 10 mIU/L is a common early pattern. HbA1c is also skewed by iron deficiency and red cell turnover, which do not affect insulin.
What can skew a fasting insulin result?
An incomplete fast is the most common cause, since milk or sugar in coffee lifts insulin sharply. Corticosteroids, some antipsychotics and pregnancy raise it, haemolysed samples can read falsely low, and insulin therapy makes the result uninterpretable. Very low-carbohydrate diets can also lower fasting insulin without showing how the client handles a mixed diet.
How long should I wait before retesting fasting insulin?
Retest after about 12 weeks, using the same lab. Insulin tends to respond over months to steady work on diet quality, sleep, stress and exercise, so earlier repeats mostly show noise. Assay differences between labs are large, so a change across two providers may reflect the method rather than the client.
References
- Royal College of Pathologists of Australasia. RCPA Manual: Insulin. Source
- Samaras K, McElduff A, Twigg SM, et al. Insulin levels in insulin resistance: phantom of the metabolic opera? Medical Journal of Australia. 2006. Source
- Matthews DR, Hosker JP, Rudenski AS, et al. Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man. Diabetologia. 1985. Source
- Royal Australian College of General Practitioners. Management of type 2 diabetes: a handbook for general practice. 2020.