Normative Predictions

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Normative Predictions

The Reference tab displays predicted CPET values from 8 validated normative equations. Predictions calculate automatically whenever patient demographics and observed CPET data are available.

Demographics have to be plausible, not just present. Systole computes nothing at all unless age is 6–100 years, height 100–250 cm, weight 15–300 kg, and sex is Male or Female. Outside those bounds the Reference tab, the Report tab and the trend charts show no predictions rather than eight implausible ones — a height typed in inches instead of centimetres (64 rather than 163) used to return negative predicted values marked "appropriate". If the table is unexpectedly empty, check the test's height, weight, age and sex first. Note that this also means no equation is offered for a patient under 6, because none is validated there.

Reference tab summary table — all 8 equations with status dots, predicted VO₂, %predicted, Z-scores, and the Report radio column

The 8 Prediction Equations

Equation	Age Range	Modality	Population	Z-Score
Jones (1985)	15–71	Cycle	General adult	No
Hansen/Wasserman (1984)	≥18	Cycle & Treadmill	Adult, weight-class adjusted	No
Cooper (1984)	<18	Cycle & Treadmill	Pediatric, height/BMI variants	No
FRIEND (2018)	20–85	Cycle & Treadmill	Large adult registry	No
Burstein (2021)	6–18	Cycle	Pediatric, race-specific (White/Black/Hispanic)	No
Blanchard (2018)	12–18	Cycle	Pediatric, BMI-corrected	Yes
Fernie (2024)	6–18	Cycle & Treadmill	Pediatric, ethnicity-adjusted	No
Amedro (2023)	6–18	Cycle	International pediatric registry	Yes

Summary Table

All 8 equations are displayed in a single table, sorted by status (green first, then yellow, then red). Each row shows:

Status dot — Green (appropriate), yellow (caution), red (inappropriate)
Predicted Peak VO₂ — Absolute (mL/min) and weight-indexed (mL/kg/min)
%Predicted — Observed ÷ predicted × 100 (when observed peak VO₂ is available)
Z-Score — Standard deviations from predicted mean (Blanchard and Amedro only)
Note — Which variant was selected and any adjustments (e.g., "Age adjusted to 18 years")
Report — Radio button to select this equation as the reference for clinical reporting
Info — Click the "i" button to view the equation formula, citation, age range, and modality

Status Colors

Color	Meaning	Example
Green	Appropriate — patient within validated population	14-year-old on cycle → Blanchard is green
Yellow	Caution — near edge of range or adjustment applied	Treadmill with cycle-based equation
Red	Not appropriate — outside validated population	8-year-old with adult equation (Jones)

Equations with age outside their validated range have their age capped to the range boundary for calculation (e.g., Fernie caps at 18 for adults) and show an adjustment note.

Detail Panel

Detail panel expanded for the Blanchard equation — status badge, predicted vs observed comparison, the full predicted-variable table grouped by exercise phase, and the cross-equation comparison toggle

Click any row to expand the full detail panel below the table (the previously expanded row collapses):

Header — Equation name, status badge, info button
Equation note — Full description of which variant and adjustments applied
Predicted vs Observed VO₂ — Side-by-side comparison with percent predicted and Z-score
All predicted variables — For Burstein, Blanchard, Fernie, and Amedro, a table of all predicted CPET variables grouped by exercise phase (Rest, AT, Peak) with observed values, %predicted, and Z-scores

Selecting a Reference for the Report

Select the Report radio button on the equation row you want to use as the normative reference. This selection:

Populates the Report tab's clinical impression with percent predicted and/or Z-score values
Drives the predicted VO₂ reference line on the 9-panel plot
Is saved with the test record
Can be changed at any time

If no equation is explicitly selected, Systole uses the site default configured in Settings (shown as "site default" in the Report tab header). The site default is resolved at display time, so changing the default in Settings immediately affects all preliminary or amended tests that don't have an explicit selection.

Verification locks the reference in. When you click Verify on a test that was using a resolved default (no explicit click on a Report radio), Systole snapshots the currently-resolved equation name into the test record at that moment. The verified test's impression will continue to render against the snapshotted equation forever, even if you later change the site default — preventing the verified clinical interpretation from drifting silently.

Choosing the Right Equation

Pediatric patients (cycle ergometry):

Blanchard is often preferred for ages 12–17 because it provides Z-scores and corrects for BMI
Amedro provides Z-scores for ages 6–18 from a large international cohort
Burstein offers race-specific equations for ages 6–18

Pediatric patients (treadmill):

Fernie covers ages 6–18 with ethnicity adjustments and separate cycle/treadmill equations
Cooper is the traditional treadmill reference for pediatric patients

Adult patients:

Hansen/Wasserman accounts for body habitus and includes a treadmill adjustment (+11%)
Jones is the standard adult cycle ergometry reference
FRIEND is based on a large US fitness registry and covers both modalities

Cross-Equation Comparison

Click Show Cross-Equation Comparison in the detail panel to view predicted values from all multi-variable datasets (Burstein, Blanchard, Fernie, Amedro) side by side. Click dataset column headers to expand comparison columns showing predicted values, Z-scores, and percent predicted. Reset Table clears column expansion state.

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