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Clinical calculator summary

G8 Geriatric Screening Tool

The classic eight-item G8 screen for geriatric vulnerabilities in older adults with cancer.

Evidence-based context for fast calculator use

Purpose:
Identify older adults who may benefit from comprehensive geriatric assessment
Population:
Originally evaluated in patients older than 70 years around first-line cancer therapy; now used more broadly in older-adult oncology with that extrapolation kept explicit
Factors:
Food intake, Weight loss, Mobility, Neuropsychological problems, BMI, More than three medications daily, Health compared with same-age peers, Age category
Reference:
Bellera et al., Ann Oncol. 2012; Soubeyran et al., PLoS One. 2014
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G8 Screening Tool

Clinical Context & Background

The classic G8 is an eight-item screening questionnaire covering food intake, weight loss, mobility, neuropsychological problems, body mass index, medication burden, self-rated health, and age. Scores range from 0 to 17, with higher scores indicating fewer vulnerabilities. A score of 14 or less is an abnormal or impaired screen and supports comprehensive geriatric assessment; a score above 14 is not abnormal at this cutoff but does not exclude vulnerability.
Bellera's original evaluation arose from patients older than 70 years around first-line chemotherapy, and ONCODAGE prospectively evaluated patients older than 70 before or during a first-line treatment sequence. The G8 is now used more broadly as an older-adult oncology screen, but that broader use should be interpreted separately from the original study population. Because age is entered categorically, this calculator cannot enforce a hard minimum age.
Primary Source EvidenceBellera CA, Rainfray M, Mathoulin-Pélissier S, et al. Ann Oncol. 2012;23(8):2166-2172. Soubeyran P, Bellera C, Goyard J, et al. PLoS One. 2014;9(12):e115060.
Formula Logic
Sum the eight classic G8 item scores (0-17 points); higher is better and a total of 14 or less is abnormal.

Reference Data

Total ScoreInterpretationAction
0-14Abnormal / impaired screenSupports comprehensive geriatric assessment.
>14-17Screen not abnormalDoes not exclude vulnerability; continue individualized assessment.

Clinical Workflow

Use, Interpret, And Continue The Patient Pathway

Expand for workflow guidance, limitations, examples, and related next steps.

When To Use

  • Use the classic G8 when a rapid vulnerability screen is needed for an older adult with cancer; the categorical age item cannot enforce a hard minimum age.
  • Use only when the patient and clinical setting match the population described for G8 Geriatric Screening Tool.

How To Interpret

  • Higher scores are better. A score of 14 or less is an abnormal or impaired screen and supports comprehensive geriatric assessment; a score above 14 is not abnormal at this cutoff but does not exclude vulnerability.
  • Interpret thresholds with the entered units, current clinical status, and local guideline context.

What To Do Next

  • When the screen is abnormal, assess function, cognition, nutrition, comorbidity, medicines, falls, mood, and social support through comprehensive geriatric assessment.
  • Document the inputs, result, clinical judgment, and any reason for deviating from the model-guided pathway.

Limitations

  • G8 is a screening tool, not a frailty diagnosis or treatment-fitness recommendation. A result above 14 does not exclude every vulnerability, and broader older-adult use extends beyond the original older-than-70 first-line-therapy populations.
  • This calculator supports clinical assessment and does not independently prescribe treatment.

Validated Population

Originally evaluated in patients older than 70 years around first-line cancer therapy; now used more broadly in older-adult oncology with that extrapolation kept explicit

Clinical example

Reduced intake, weight loss, limited mobility, and more than three medications per day lower the G8 total and can support referral for comprehensive geriatric assessment.

Calculation verification history

Verified

  1. : Production browser revalidation

    • Three source-backed G8 cases passed through visible production controls at scores 0, exact 14, and 17.
    • The former valid-visible-selection and zero-valued-option failures were absent; no unexpected N/A, literal undefined value, stale control, or browser-console error was observed.
    Download latest production check (Excel)

    Case-level evidence is retained in validation/browser-revalidation/g8-geriatric-screening-2026-08-03.json.

  2. : Local browser remediation verified; production retest pending

    • Updated the public select adapter to accept the exact numeric option values emitted by the shared browser form while preserving the strict eight-key numeric calculation engine.
    • Ten local browser cases passed through visible controls, including the 0 and 17 extremes, 13.5/14/14.5 cutoff transitions, alternate item branches, required-field feedback, and reset/repeat behavior.
    • The original failed production-browser record remains open until this change is deployed and the public route passes a new ten-case browser run.

    Local diagnostic evidence is retained in validation/browser-production/g8-geriatric-screening.local-remediation.json.

  3. : Production browser validation

    • Ten source-backed cases were exercised on the public production route through visible browser controls; 1/10 case records passed their expected-versus-observed assertions across 12 visible submissions.
    • Overall browser status: failed-calculation-ui-and-console. critical: Production rejects fully completed G8 forms even though all eight intended options are visibly selected immediately before Calculate is clicked. | critical: A fully completed all-minimum case using the valid zero-valued option in every control is blocked before a result card renders. | medium: Production emitted minified React error #418 during route loads/reloads used by this run.
    • Case-level inputs, expected and observed results, reset/repeat behavior, failure reproductions, and console evidence are retained in the production-browser evidence record.

    Case-level production evidence is retained in validation/browser-production/g8-geriatric-screening.json.

  4. : Calculation verification

    • Implemented the classic eight-item G8 with exact source-form option weights, a 0-17 total, and the abnormal or impaired cutoff at 14 or less.
    • Passed 106/106 minimum, maximum, 13.5/14/14.5 boundary, every-option, strict invalid-input, no-default, label, and UI-serialization checks.
    • Separated the original older-than-70 first-line-therapy populations from broader older-adult use and removed treatment-fitness recommendations.

Verification confirms the calculator implementation against the cited model; it is not independent clinical validation, regulatory approval, or medical advice.

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Frequently Asked Questions

What is G8 Geriatric Screening Tool used for?

Identify older adults who may benefit from comprehensive geriatric assessment. It is intended for originally evaluated in patients older than 70 years around first-line cancer therapy; now used more broadly in older-adult oncology with that extrapolation kept explicit.

Does G8 Geriatric Screening Tool determine treatment by itself?

No. Confirm the population, inputs, contraindications, competing risks, and current guideline recommendations before acting on the result.

Evidence-based oncology decision support. Verify with clinical guidelines.