This QUICKI calculator computes the Quantitative Insulin Sensitivity Check Index from fasting insulin and glucose — the log-based sibling of HOMA-IR with a tighter correlation to clamp-measured insulin sensitivity.

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QUICKI = 1 ÷ [log₁₀(Insulin) + log₁₀(Glucose)] — HOMA-IR Through a Log Lens

Katz et al. (2000) showed the log transform straightens the skewed insulin distribution, making QUICKI track the euglycemic clamp (the research gold standard) better than raw HOMA in several cohorts. Its sibling index lives on our HOMA-IR Calculator — same two inputs, opposite direction: HOMA-IR rises with resistance; QUICKI falls. Part of our Health Calculators collection.

Worked Example (Verified)

  • Insulin 12 µU/mL, glucose 100 mg/dL (defaults): log 12 = 1.079, log 100 = 2.000 → QUICKI = 1 ÷ 3.079 = 0.325 — borderline band; the matching HOMA-IR for the same labs is 2.96, telling the same story from the resistance side
  • Sensitive contrast: insulin 5, glucose 85 → 1 ÷ (0.699 + 1.929) = 0.380 — the lean, insulin-sensitive profile
  • The log’s mercy: doubling insulin moves QUICKI modestly (logs compress), which is exactly why the index behaves statistically where raw products explode
  • Units discipline: glucose must be mg/dL (mmol/L × 18) and insulin µU/mL — log formulas are brutally unit-sensitive

Using QUICKI Honestly

  • Research contexts dominate: epidemiology and intervention studies, rarely individual diagnosis.
  • Insulin assays vary between manufacturers — cutoffs from one paper transfer imperfectly to another lab.
  • Fasting state is mandatory; post-meal insulin breaks the model’s assumptions completely.
  • Neither QUICKI nor HOMA-IR replaces dynamic testing (OGTT-derived indices, clamp) where precision matters.

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Frequently Asked Questions

How do you calculate QUICKI?

QUICKI = 1 ÷ [log₁₀(fasting insulin µU/mL) + log₁₀(fasting glucose mg/dL)]. Insulin 12 and glucose 100: 1 ÷ (1.079 + 2.000) = 0.325. Higher means more insulin-sensitive — the opposite direction of HOMA-IR, computed from the same two fasting values.

What is a normal QUICKI value?

Published healthy cohorts cluster around 0.35–0.40 (the frequently cited mean for normal-weight, glucose-tolerant adults is ≈ 0.382), while obesity and type 2 diabetes cohorts average ≈ 0.33 and ≈ 0.30. Treat bands as literature context — insulin assay differences move the numbers between labs.

QUICKI vs HOMA-IR — which is better?

They use identical inputs; QUICKI’s log transform normalizes insulin’s skewed distribution, and several validation studies found it correlates slightly better with clamp-measured sensitivity — particularly across wide insulin ranges. HOMA-IR is more widely reported clinically. For most purposes they rank patients identically, in mirror image.

Can QUICKI diagnose insulin resistance?

No standalone index diagnoses it. QUICKI quantifies a fasting surrogate used in research; clinical assessment weaves in glucose tolerance, lipids, blood pressure, anthropometrics and history. A low QUICKI is a prompt for proper evaluation, not a verdict.

Why logarithms?

Fasting insulin is heavily right-skewed (a few large values dominate products like HOMA-IR). Logs compress that skew into a near-normal distribution, stabilizing correlations — Katz’s 2000 derivation showed the resulting index tracks clamp glucose disposal rates linearly across lean, obese and diabetic ranges.

Is this QUICKI calculator free?

Yes — free, instant, no sign-up. An educational/research aid, not a diagnostic tool.