Reference interval software for clinical laboratories Six quantile methods including robust and bootstrap approaches, partitioning by sex, age, or ethnicity, full range of transformations, outlier screening, normality assessment, and transfer and verification of existing intervals — the widest range of reference interval methods in any software package.

Establish the reference ranges clinicians depend on

Every laboratory result a clinician sees is interpreted against a reference interval. If the interval is wrong — too wide, too narrow, derived from the wrong population, or not partitioned where it should be — normal patients get flagged and abnormal patients get missed. Establishing defensible reference intervals from your own population, or verifying that a manufacturer’s intervals apply to your patients, is one of the most consequential statistical tasks a laboratory performs.

Six quantile methods to match your sample size and distribution. Partition by any factor when subgroups need separate ranges. Screen outliers, assess normality, apply transformations when the raw distribution doesn’t fit. Transfer existing intervals to a new method using regression, or verify them with a binomial test.

I purchased Analyse-it and I love it. Thank you so much for the superb and easy to use program. Technical support is the best I have ever seen.
Addy Alsumidaie, MD, Ph.D.
Director, Clinical Development
Johnson and Johnson

What's included

Choose from six quantile methods to match your sample size and distribution

Parametric quantiles when the distribution is Gaussian. Non-parametric with three computation approaches — (N+1)p, Np+½, (N+⅓)p+⅓ — when you have 120+ observations. Robust bi-weight for small or moderately skewed samples. Bootstrap for distribution-free estimation. Harrell–Davis for a smooth quantile estimate. Confidence intervals on all reference limits.

Partition by factors that require separate reference ranges

Partition by sex, age group, ethnicity, or any combination of factors — such as separate calcium intervals for males and females, or age-stratified alkaline phosphatase ranges for paediatric populations. Outlier screening and normality assessment run independently for each subgroup.

Screen outliers and assess normality before establishing limits

Tukey box plots for outlier identification. Shapiro–Wilk and Anderson–Darling normality tests. Frequency histogram with normal overlay. Normal Q–Q plot with Lilliefors confidence band.

Apply transformations when the raw distribution doesn’t fit

Log, square root, Box–Cox, Manly exponential, and two-stage exponential/modulus transformations. Choose the transformation that achieves the best fit, compute parametric reference limits on the transformed scale, and back-transform to original units. Reciprocal and cube root also available.

Transfer existing intervals or verify them against your patient population

Transfer a reference interval from one measurement procedure to another using the regression function from a method comparison study. Verify that a manufacturer’s published interval applies to your patient population with a binomial test — such as confirming that at least 90% of 20 reference individuals fall inside the claimed interval.

Example analyses

See reference interval results in detail — partitioned intervals, histograms with reference limits, and outlier screening — using example datasets you can download and follow along with.

Calcium reference intervals, partitioned by sex. Non-parametric (N+1)p quantile method, 120 observations per group. Histogram with reference limits and 90% CIs.

Part of the Medical edition

Reference intervals are one part of the Medical edition, alongside diagnostic accuracy, Bland–Altman agreement, and survival analysis — plus the full Standard edition for hypothesis testing, regression, and descriptive statistics.

For formal method validation with CLSI EP28-A3C protocol support, see the Method Validation edition.

Software you can trust

Validated calculations you can defend at peer review Every calculation is performed by Analyse-it — no Excel formulas, no third-party functions. Results are validated against published datasets and thousands of internal test cases before every release. See how we develop and validate Analyse-it →
Patient data stays on your PC Analyse-it runs entirely within Microsoft Excel on your PC. No cloud processing, no data transmission. Patient data and research data stay within your facility under your own data governance controls.
Standard Excel workbooks anyone can open Every analysis is an ordinary .xlsx workbook. Share with co-authors, attach to a manuscript submission, archive for publication queries. No proprietary format, no licence required to view results. Co-authors and reviewers see exactly what you see.
Results that can’t be accidentally broken Analysis output contains computed values, not formulas. Nothing to accidentally overwrite, no cell references to break, no formula errors to introduce. The results you published are exactly what you’ll find when you reopen the workbook months or years later when a reviewer asks.

Technical details

Establish reference limits

  • Normal (parametric) quantile
  • Non-parametric quantile: (N+1)p, Np+½, (N+⅓)p+⅓
  • Harrell–Davis quantile
  • Bootstrap quantile
  • Robust bi-weight quantile for symmetric and skewed small samples
  • Confidence intervals on all reference limits

Transfer / verify

  • Transfer existing reference interval using method comparison regression function
  • Binomial test for proportion inside reference interval

Partitioning & transformations

  • Partition by factor(s) new in v4.00
  • Reciprocal transformation
  • Log transformation
  • Square and cube root
  • Box–Cox new in v3.52
  • Manly exponential new in v4.00
  • Two-stage exponential / modulus new in v4.00

Normality testing

  • Shapiro–Wilk test
  • Anderson–Darling test
  • Normal Q–Q plot with Lilliefors confidence band

Plots

  • Frequency distribution histogram with normal overlay and reference limits
  • Tukey outlier box plot
  • Normal Q–Q plot with Lilliefors confidence band