Growth Screening Flag Checker

Reference sex:

Use the reference curve recorded for the child's growth-chart series.

Review sensitivity:

Choose how early the workflow should suggest reassessment after the same screening result.

Visit rows:

One row per visit as age_months,height_cm,weight_kg; 2–30 rows, ages 0–240 months.

Samples contain fictional measurements and no personal identifiers.

Calculated locally with simplified screening anchors. Confirm measurements on an official chart before acting.

Reference policy:

Auto matches the U.S. chart-family transition; fixed options support continuity review only.

Gestational age at birth:

Enter 40 when corrected age is not used.

weeks

Corrected-age window:

Choose 12–36 chronological months; default 24.

months

Band-crossing alert:

Choose 1–4 major bands; default 2.

Percentile-drop alert:

Choose 8–40 percentage points; default 25.

points

High-adiposity alert:

Choose 85th–99th percentile; default 95th.

percentile

Adiposity persistence:

Choose 1–3 visits; default 1.

visits

Height-velocity guardrail:

Use age-based unless a screening program defines a custom floor.

Custom velocity floor:

Choose 2–10 cm/year; default 4.

cm/year

Velocity persistence:

Choose 1–2 intervals; default 1.

intervals

Mother height:

Enter 0 to omit family-height context.

Father height:

Enter 0 to omit family-height context.

Family target band:

Choose 4–15 cm; default 8.5.

± cm

Severity	Signal	Evidence	Next step	Copy
{{ row.severity }}	{{ row.signal }}	{{ row.evidence }}	{{ row.next_step }}

Age	Screening age	Reference	Height	Weight	Adiposity	BMI	Velocity	Status	Copy
{{ formatNumber(row.age_months, 1) }} mo	{{ formatNumber(row.screening_age_months, 1) }} mo corrected	{{ row.reference }}	P{{ formatNumber(row.height_percentile, 1) }}	P{{ formatNumber(row.weight_percentile, 1) }}	{{ row.adiposity_label }} P{{ formatNumber(row.adiposity_percentile, 1) }}	{{ formatNumber(row.bmi, 2) }}	{{ row.height_velocity_cm_per_year === null ? '—' : formatNumber(row.height_velocity_cm_per_year, 2) + ' cm/yr' }}	{{ row.velocity_status }}

One measurement can be unusual without showing a growth problem. The stronger signal is a series of accurate measurements that moves away from the child’s earlier pattern, crosses several percentile bands, or shows slower height gain than expected for age. Growth screening organizes those clues so a questionable value can be checked before it is treated as a trend.

A percentile describes position within a reference distribution. It is not a grade, and the 50th percentile is not a target every child should approach. Family stature, prematurity, measurement technique, illness, nutrition, puberty, and the choice of reference chart can all change the position or its meaning. Consistency over time usually matters more than a small movement between neighboring percentiles.

Chronological age: Time since birth, used to order visits and measure the interval between them.
Corrected age: Age adjusted for weeks born before 40 weeks during a selected early-life window.
Weight-for-length: Weight interpreted against recumbent length, used here before a screening age of 24 months.
BMI-for-age: Body mass index interpreted against age and sex, used from a screening age of 24 months.
Height velocity: Annualized height gain between two visits, expressed in centimetres per year.

The transition at 24 months deserves care. U.S. guidance changes from World Health Organization (WHO) growth standards to Centers for Disease Control and Prevention (CDC) charts, and also changes from length to standing height and from weight-for-length to BMI-for-age. A visible percentile shift at that boundary may come from the changed measurement and reference, not from a sudden change in the child.

Serial screening is a prompt to verify measurements and seek qualified review, not a diagnosis. These calculations use simplified interpolated anchors rather than official WHO or CDC LMS chart data, so any flag should be confirmed on the appropriate official chart and interpreted with the child’s clinical context.

How to Use This Tool:

Start with the same sex-specific chart series used for the child’s record, then enter visits in chronological order.

Choose Reference sex and Review sensitivity. Sensitivity changes only the suggested follow-up interval, not percentiles or flags.
Enter Visit rows as age in months, height in centimetres, and weight in kilograms. Use 2 to 30 rows with different ages; if an age appears twice, the last row is kept and a verification flag is added.
Set Advanced options only when the record needs them. Corrected age, chart-family routing, band and percentile cutoffs, adiposity persistence, velocity rules, and paired parent heights can all change the screen.
Review Screening flags first, then check the matching visit values and trajectory. Re-measure or correct dates and units before using a flag to plan follow-up.

Interpreting Results:

The overall status follows the most consequential active evidence. Immediate review means at least one critical rule fired. Near-term reassessment means a watch rule fired without a critical rule. Verify data quality is reserved for timing, duplicate-age, or implausible-velocity concerns when no stronger flag is present. Routine surveillance means none of the active screening rules fired.

Read a flag together with its evidence and the visit ledger; the label alone does not show whether measurement error, chart transition, illness, or a persistent trajectory caused it.
A clean result means only that the selected simplified rules were not triggered. It does not establish normal growth or exclude a condition.
Confirm an unexpected result with accurate repeat measurements and the appropriate official chart. Urgent symptoms or clinical concern should be addressed directly with a qualified health professional.

Technical Details:

Each visit is compared with sex-specific, age-interpolated height, weight, BMI, or weight-for-length anchors. The reference family can be fixed, or routed automatically to WHO-style anchors before 24 screening months and CDC-style anchors from 24 months. These are repository-authored approximations and do not reproduce official LMS calculations.

Formula Core:

Body mass index uses weight in kilograms and height in metres.

BMI = \frac{w}{{h / 100}^{2}}

A simplified z-score measures distance from the selected anchor median in anchor standard deviations. A normal cumulative distribution approximation then converts that z-score to a percentile, limited to 0.1 through 99.9.

z = \frac{x - m}{s} P = 100 \times Φ (z)

Here, x is the measured height, weight, BMI, or weight-for-length value; m is the adjusted anchor median; s is the adjusted anchor standard deviation; and P is the resulting percentile.

For a child born before 40 completed weeks, correction subtracts the weeks early while chronological age remains below the selected correction window.

A_{screen} = \max (0, A_{chron} - \frac{\max (0, 40 - G)}{4.3482142857})

G is gestational age in completed weeks. At or beyond the correction-window boundary, screening age equals chronological age.

Height velocity annualizes the change between adjacent visits. Intervals shorter than two months or longer than 18 months produce verification cues because annualization can amplify error or hide short-term change.

v = \frac{H_{2} - H_{1}}{A_{2} - A_{1}} \times 12

Heights are in centimetres and ages are in months, so v is centimetres per year. A value below the active floor is Low; a value from the floor up to but not including 115% of the floor is Borderline.

When both parent heights are supplied, the family target midpoint and its lower comparison edge are calculated as follows.

H_{target} = \frac{H_{father} + H_{mother} + S}{2} H_{low} = H_{target} - B

S is +13 cm for male reference sex and −13 cm for female reference sex; B is the selected family target band. The projected adult height is an anchor-based screening estimate, not a prediction.

Rule Core:

The rule order separates critical growth signals, watch signals, and measurement-quality checks. A comparison at a cutoff uses the operators shown below.

Growth screening rules and exact boundaries
Signal	Exact rule	Result
Latest height position	Percentile < 3; otherwise percentile < 10	Critical; otherwise Watch
Latest low weight or adiposity	Percentile < active low cutoff	Critical
Severe BMI screen	Age-routed BMI at least 120% of the simplified BMI 95th-percentile value	Critical
Persistent high adiposity	Consecutive latest values ≥ the active high cutoff for the selected number of visits	Watch
Height channel drift	Major-band drop ≥ selected band count, or percentile drop ≥ selected point threshold	Critical
Recent height velocity	Consecutive latest intervals below the floor ≥ selected persistence	Critical
Family target comparison	Age ≥ 24 months and projected height < family lower edge	Watch; Critical when the gap is > 5 cm
Measurement quality	Duplicate age, interval < 2 months, interval > 18 months, or post-24-month velocity < 0 or > 18 cm/year	Verify

Before 24 screening months, adiposity uses weight-for-length. Its low and high cutoffs are the 2nd and 98th percentiles under WHO-style routing; other routes use a 5th-percentile low cutoff and the selected high-adiposity cutoff. From 24 months, adiposity uses BMI-for-age with the 5th-percentile low cutoff.

The suggested follow-up interval starts at 0.5 month for any critical flag, 1 month for any watch flag, 1.5 months for verification-only evidence, or 3 months when no flag fires. Earlier review multiplies that value by 0.5, Balanced by 1, and Later review by 2; the result is rounded to the nearest quarter-month and limited to 0.25 through 6 months. This timing is a local triage aid, not clinical guidance.

Limitations and Privacy Notes:

Growth measurements and family heights can be sensitive health information. Calculations run in the browser, but copied, downloaded, or shared results can contain the entered measurements.

The simplified anchors are not official WHO or CDC LMS tables and should not be used for diagnosis or treatment.
Length, standing height, clothing, scale calibration, hydration, visit timing, and data-entry units can materially change a flag.
Family-height and adult-height estimates omit puberty timing, health history, genetics beyond parental stature, and clinical examination.

Worked Examples:

Stable reference positions

Female WHO-style rows at 12 months (74.222 cm, 9.0602 kg) and 24 months (86.6592 cm, 11.707 kg) place height and weight at the simplified 50th percentile at both visits. Height velocity is 12.4372 cm/year against a 6 cm/year floor, so the default rules return Routine surveillance.

A short interval that needs verification

Female WHO-style rows at birth (49.2473 cm, 3.2576 kg) and one month (50 cm, 3.5 kg) annualize to 9.0324 cm/year against a 12 cm/year floor. The height position also falls from the simplified 50th to about the 14.83rd percentile. The screen reports critical drift and low velocity, plus a verification cue because a one-month interval can magnify measurement error.

References:

Growth Charts, Centers for Disease Control and Prevention, September 2, 2024.
Using WHO Growth Standard Charts, Centers for Disease Control and Prevention, March 20, 2024.
Child and Teen BMI Categories, Centers for Disease Control and Prevention.