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NephrologyRisk Assessment

Contrast-Associated AKI Prevention (ACR-NKF/RANZCR)

Contrast-Associated AKI Prevention (ACR-NKF/RANZCR): Iodinated Contrast Planned (Adult) → Check Kidney Function Risk → Contrast Route? → IV or Intra-art...

Pathway Overview

21 steps

Algorithm Steps

21 total

  1. 01Start

    Iodinated Contrast Planned (Adult)

    Adults only. Children: use bedside Schwartz eGFR and a paediatric protocol.

  2. 02Action

    Check Kidney Function Risk

    Life-threatening emergency: do not delay the scan for a creatinine result or IV fluids.

    • Check eGFR if: CKD, kidney transplant or single kidney, previous AKI, dialysis, kidney surgery or ablation, albuminuria, diabetes, metformin use
    • Use a recent eGFR: within 7 days if inpatient or acutely unwell; within 3 months if stable
    • eGFR is not reliable in AKI: treat known or suspected AKI as high risk
    • Children: this adult pathway does not apply; use bedside Schwartz eGFR and a paediatric protocol
    • No risk factor and routine scan: no creatinine needed
  3. 03Decision

    Contrast Route?

    IV (eg CT) or intra-arterial with second-pass renal exposure, versus intra-arterial with first-pass renal exposure

  4. IV or intra-arterial second-pass
  5. 04Decision

    IV or Intra-arterial Second-Pass: eGFR and AKI Status

    Stable eGFR ≥45, 30-44, <30 or AKI, on maintenance dialysis, or emergency with eGFR unknown

  6. eGFR ≥45
  7. 05Action

    eGFR ≥45 (Stable): No Prophylaxis

    IV contrast is not an independent risk factor for AKI at this eGFR.

    • Standard diagnostic contrast dose
    • No IV fluids needed
    • Continue metformin
  8. 06End

    Proceed Without Prophylaxis

    Continue metformin. No routine creatinine recheck.

  9. eGFR 30-44
  10. 07Action

    eGFR 30-44 (Stable): Prophylaxis Not Routine

    Routine IV fluids are not recommended at this eGFR.

    • Standard diagnostic contrast dose
    • Continue metformin if no AKI
  11. 08Decision

    eGFR 30-44: Extra Risk Present?

    Recent AKI, falling or borderline eGFR, or many risk factors. Yes: IV saline prophylaxis (next step). No: proceed without prophylaxis.

  12. If Yes
    1. 09Action

      IV Saline Prophylaxis (Not if Heart Failure or Overload)

      For eGFR <30, AKI, dialysis with urine output, or selected eGFR 30-44. Heart failure or fluid overload: no routine IV fluids; decide with the treating team.

      • Adult: 0.9% sodium chloride IV 1 mL/kg/h (max 100 mL/h) from 1 h before to 3-12 h after contrast
      • Metformin, if eGFR <30 or AKI: stop at the time of contrast; withhold 48 h; restart only after eGFR is rechecked and stable
      • Standard diagnostic contrast dose; do not reduce it ad hoc. Low- or iso-osmolar agent
      • Stop nonessential nephrotoxins (eg NSAIDs). Consider withholding ACE inhibitor or ARB for 48 h before an elective scan
      • Emergency with no time for pre-scan fluids: fluids after the scan may be considered
      • Not recommended: N-acetylcysteine, sodium bicarbonate, diuretics, or dialysis to remove contrast
    2. 10Action

      At-Risk Patients: Recheck Creatinine at 48-72 h

      Applies after prophylaxis, an emergency scan with eGFR unknown, or intra-arterial first-pass contrast in an at-risk patient.

      • AKI (KDIGO): creatinine rise ≥26.5 µmol/L within 48 h, or ≥1.5 × baseline within 7 days
      • Restart metformin only when eGFR is rechecked and stable
      • Restart ACE inhibitor or ARB when creatinine is at baseline
    3. 11Decision

      AKI After Contrast?

    4. If Yes
      1. 12Outcome

        AKI After Contrast: Supportive Care

        Keep nephrotoxins and metformin stopped until kidney function recovers. Nephrology review if severe. Monitor eGFR for at least 30 days.

      If No
      1. 13Outcome

        No AKI: Usual Care

        Creatinine stable. Restart held medicines.

    If No
    1. Path rejoins step 06Shared downstream outcome
  13. eGFR <30 or AKI
  14. 14Warning

    eGFR <30, AKI or Dialysis With Urine Output: High Risk

    Relative, not absolute, contraindication. Do not withhold contrast for a life-threatening diagnosis. Dialysis with urine output: discuss with the renal physician.

    • Discuss with the radiologist: consider non-contrast CT, ultrasound or non-contrast MRI
    • Heart failure or fluid overload: no routine IV fluids; decide with the treating team
    • Metformin: stop at the time of contrast; withhold 48 h
  15. 15Decision

    High Risk: Is Contrast Needed?

    Weigh benefit against AKI risk with the radiologist. Yes: IV saline prophylaxis step. No: alternative imaging.

  16. If Yes
    1. Path rejoins step 09Shared downstream outcome
    If No
    1. 16Action

      High Risk, Contrast Not Needed: Alternative Imaging

      Use imaging without iodinated contrast.

      • Non-contrast CT, ultrasound or non-contrast MRI
      • Gadolinium MRI has its own kidney rules (NSF risk)
    2. 17End

      Reassess If Result Is Not Diagnostic

      Review the need for contrast again with the radiologist.

  17. On dialysis
  18. 18Decision

    On Maintenance Dialysis: Anuric, No Working Transplant?

    Yes (no urine output and no functioning kidney transplant): proceed. No (passes urine, HD or PD, or functioning transplant): follow the high-risk step.

  19. If Yes
    1. 19End

      Anuric on Dialysis, No Functioning Transplant: Proceed

      No prophylaxis. Do not start or reschedule dialysis because of the contrast.

    If No
    1. No: passes urine
    2. Path rejoins step 14Shared downstream outcome
  20. Emergency, eGFR unknown
  21. 20Action

    Emergency, eGFR Unknown: Scan Now

    Do not wait for creatinine. Manage as eGFR <30 as far as the emergency allows (IV saline step).

    • Send creatinine; do not delay the scan for the result
    • Metformin: stop at the time of contrast; withhold 48 h; check eGFR before restart
    • Heart failure or fluid overload: no routine IV fluids
  22. Path rejoins step 09Shared downstream outcome
  23. Intra-arterial first-pass
  24. 21Action

    Intra-arterial, First-Pass Renal Exposure

    Eg coronary, renal or visceral angiography. At risk if eGFR <45, AKI or eGFR unknown. Emergency (eg primary PCI): do not delay for creatinine or fluids. Heart failure (NYHA 3-4) or CKD 5: individualise fluids.

    • Follow the cardiology or interventional protocol
    • At risk: 0.9% sodium chloride IV 1 mL/kg/h (adult; max 100 mL/h) for 3-4 h before and 4-6 h after contrast
    • Metformin: stop if eGFR <45, unknown, or unwell; withhold 48 h; check eGFR before restart
    • Lowest contrast dose for a diagnostic result
  25. Path rejoins step 10Shared downstream outcome

Guideline Source

ACR-NKF Consensus Statements: Use of IV Iodinated Contrast Media in Patients with Kidney Disease (Radiology 2020); ACR Manual on Contrast Media 2026

DOI: 10.1148/radiol.2019192094View Guideline

Clinical Safety Information

Clinical Decision Support — Not a Substitute for Clinical Judgment

Individual patient factors may require deviation from these recommendations.

Known Limitations

  • Intra-arterial first-pass renal exposure (eg coronary angiography): thresholds and fluids differ; follow the procedural protocol
  • Evidence for prophylaxis is weak and IV contrast risk may be overstated; withholding contrast can delay diagnosis
  • Does not cover gadolinium, contrast allergy or thyroid risk
  • eGFR is not reliable in AKI

Contraindicated Populations

Children (use bedside Schwartz eGFR and a paediatric protocol)Heart failure or fluid overload: IV fluid prophylaxis needs an individual decision

Applicable Regions

AUUSEUglobal

AU: RANZCR Iodinated Contrast Media Guideline V2.3 (2018): no precautions if eGFR >45; routine IV fluids not recommended for eGFR 30-45; eGFR <30 or AKI: weigh risk and consider IV 0.9% saline. Metformin: IV contrast stop if eGFR <30, unknown or unwell; intra-arterial stop if eGFR <45.

EU: ESUR 2018: at risk if eGFR <30 (IV or intra-arterial second-pass) or <45 (intra-arterial first-pass or ICU), or AKI.

US: ACR-NKF 2020 consensus and ACR Manual on Contrast Media (2026).

Version 2Next review: 2027-09-30

Related Nephrology Pathways

Acute Kidney Injury (AKI) Management (KDIGO)

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Chronic Kidney Disease (CKD) Evaluation and Management (KDIGO 2024)

Management

Glomerulonephritis Evaluation (KDIGO 2021)

Diagnostic

Hepatorenal Syndrome (HRS-AKI) Management (ICA-ADQI 2024 / EASL)

Management

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eGFR (CKD-EPI 2021)

Estimated glomerular filtration rate using CKD-EPI 2021 equation (race-free)

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Frequently Asked Questions

What is the Contrast-Associated AKI Prevention (ACR-NKF/RANZCR)?

The Contrast-Associated AKI Prevention (ACR-NKF/RANZCR) is a risk assessment clinical algorithm for Nephrology. It provides a structured decision tree to guide clinical decision-making, based on ACR-NKF Consensus Statements: Use of IV Iodinated Contrast Media in Patients with Kidney Disease (Radiology 2020); ACR Manual on Contrast Media 2026.

What guideline is the Contrast-Associated AKI Prevention (ACR-NKF/RANZCR) based on?

This algorithm is based on ACR-NKF Consensus Statements: Use of IV Iodinated Contrast Media in Patients with Kidney Disease (Radiology 2020); ACR Manual on Contrast Media 2026 (DOI: 10.1148/radiol.2019192094).

What are the limitations of the Contrast-Associated AKI Prevention (ACR-NKF/RANZCR)?

Known limitations include: Intra-arterial first-pass renal exposure (eg coronary angiography): thresholds and fluids differ; follow the procedural protocol; Evidence for prophylaxis is weak and IV contrast risk may be overstated; withholding contrast can delay diagnosis; Does not cover gadolinium, contrast allergy or thyroid risk; eGFR is not reliable in AKI. Individual patient factors may require deviation from these recommendations.

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