Source: https://guthlabs.ai/docs/instruments/egfr-mdrd-legacy/

instrument / verified-clean

# eGFR (MDRD, legacy)

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Inspectable records

[01**Overview**Purpose and lifecycle](<https://guthlabs.ai/docs/instruments/egfr-mdrd-legacy/>)[02**Mechanism**Method and assumptions](<https://guthlabs.ai/docs/instruments/egfr-mdrd-legacy/mechanism/>)[03**Implementation**Binding and validation](<https://guthlabs.ai/docs/instruments/egfr-mdrd-legacy/implementation/>)[04**Qualification**Evidence and errata](<https://guthlabs.ai/docs/instruments/egfr-mdrd-legacy/qualification/>)

## Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

**Area**: Biology, Medicine & Pharmacology (educational estimates only — every panel labeled not-medical-advice)

**Tranche**: tranche-4

**Evidence ID**: t4-026

**Ledger rows**: 1

No ledger note is attached.

## Review findings

Educational estimate only and not medical advice, consistent with the supplied honest label. The catalog must explicitly identify whether this is the race-free IDMS-traceable MDRD variant with coefficient 175, rather than another historical MDRD variant.

### Formula and scope findings

- The formula is correct for the IDMS-traceable 4-variable MDRD equation without a race coefficient: 175×SCr^-1.154×Age^-0.203×(0.742 if female). However, 'MDRD, legacy' is ambiguous because historical MDRD variants commonly used a 186 coefficient and, in older implementations, an additional Black race coefficient; the intended variant must be named explicitly.

- The input 'sex' is underspecified: the formula defines a female multiplier, but behavior for unknown, nonbinary, or missing values is not stated.

### Unit assumptions

- Age is in completed years and serum creatinine is in mg/dL.

- The output is normalized to a body-surface area of 1.73 m² and is reported in mL/min/1.73 m².

- If serum creatinine is supplied in µmol/L, convert using SCr_mg/dL = SCr_µmol/L ÷ 88.4 before applying the formula.

- The 0.742 multiplier applies only when the selected formula convention classifies the patient as female; otherwise the multiplier is 1.

## Boundary hardening

**BREAK_CLAIMED** · SELF_FLAGGED

The formula has undefined or non-physiologic boundary inputs that require validation: age = 0 produces an infinite mathematical result, negative serum creatinine produces an undefined real power, and an unspecified creatinine unit can produce an orders-of-magnitude error.

## Errata and corrections

No applied erratum is attached to this unique-name record.

## Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

````
{
  "inputs": {
    "age_years": 60,
    "sex": "male",
    "serum_creatinine_mg_dL": 1
  },
  "expected_outputs": {
    "eGFR_mL_min_1_73m2": 76.22
  },
  "working": "SCr^-1.154 = 1.0^-1.154 = 1.000. Age^-0.203 = 60^-0.203 ≈ 0.43555. Male multiplier = 1.000. eGFR = 175 × 1.000 × 0.43555 × 1.000 = 76.22 mL/min/1.73 m²."
}
````

## Related workflows

[Renal Dosing Chain (education)cross-check eGFR](<https://guthlabs.ai/docs/instrument-workflows/renal-dosing/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json · VERIFIED_CLEAN`

- `evidence-tranche4/tranche4-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`