_id

683a165bc782e11e38d1b389

id

10550

title

Acute Interstitial Nephritis (AIN) Risk Calculator

full_title

Acute Interstitial Nephritis (AIN) Risk Calculator

short_title

AIN Risk Calculator

med_description

Identifies the likelihood of acute interstitial nephritis in at-risk patients.

short_description

Acute interstitial nephritis risk.

slug

acute-interstitial-nephritis-ain-risk-calculator

description

The Acute Interstitial Nephritis (AIN) Risk Calculator identifies acute interstitial nephritis in the at-risk population.

keywords

Acute Interstitial Nephritis (AIN) Risk Calculator, AIN Risk Calculator, AIN, acute interstitial nephritis, acute kidney injury, AKI, kidney biopsy, AIN diagnosis, kidney damage, urine protein, BUN, creatinine, AIN risk, acute interstitial nephritis risk

complaint

[ "Arthralgia", "Back Pain", "Fever", "Flank Pain", "Hematuria", "Nausea", "Oliguria", "Weakness" ]

formula

evidence

measurements

[ { "name": "Creatinine", "unit": "cr", "error_min": "0.01", "error_max": "40", "warn_min": "0", "warn_max": "10", "conversion": "88.4", "normal_max_si": "115", "normal_max_us": "1.3", "normal_min_si": "62", "normal_min_us": "0.7", "units_si": "µmol/L", "units_us": "mg/dL" }, { "name": "AIN prevalence", "unit": "ain_prev", "error_min": "0", "error_max": "1", "warn_min": "0", "warn_max": "1", "conversion": "1", "normal_max_si": "1", "normal_max_us": "1", "normal_min_si": "0", "normal_min_us": "0", "units_si": "", "units_us": "" }, { "name": "BUN", "unit": "bun", "error_min": "1", "error_max": "500", "warn_min": "2", "warn_max": "300", "conversion": "0.357", "normal_max_si": "7.1", "normal_max_us": "20", "normal_min_si": "2.9", "normal_min_us": "8", "units_si": "mmol/L", "units_us": "mg/dL" }, { "name": "Urine specific gravity (AIN)", "unit": "urgrav", "error_min": "1", "error_max": "1.05", "warn_min": "1.004", "warn_max": "1.04", "conversion": "1", "normal_max_si": "1.04", "normal_max_us": "1.04", "normal_min_si": "1.004", "normal_min_us": "1.004", "units_si": "", "units_us": "" } ]

information

Sum = (0.8367518 × log(creatinine)) + (-0.9181938 × log(BUN creatinine ratio)) + (-0.0501203 × 1000 × (urine specific gravity - 1)) + urine dipstick protein* + 0.770398 + log(local prevalence of AIN among all biopsies**/0.23)

% Probability of AIN = 100 × e^sum / (1+ e^sum) 

* 0.9360127 if urine dipstick protein is 1+ or lower, otherwise 0

** If unknown, enter 0.23

refrences

{ "Clinical Practice Guidelines": [], "Manufacturer Website": [], "Original/Primary Reference": [ { "href": "https://pubmed.ncbi.nlm.nih.gov/34865148/", "text": "Moledina DG, Eadon MT, Calderon F, et al. Development and external validation of a diagnostic model for biopsy-proven acute interstitial nephritis using electronic health record data. Nephrol Dial Transplant. 2022;37(11):2214-2222." } ], "Other References": [], "Outcomes": [], "Validation": [ { "href": "https://pubmed.ncbi.nlm.nih.gov/34865148/", "text": "Moledina DG, Eadon MT, Calderon F, et al. Development and external validation of a diagnostic model for biopsy-proven acute interstitial nephritis using electronic health record data. Nephrol Dial Transplant. 2022;37(11):2214-2222." }, { "href": "https://pubmed.ncbi.nlm.nih.gov/39500309/", "text": "Moledina DG, Shelton K, Menez S, et al. External Validation of an Electronic Health Record–Based Diagnostic Model for Histological Acute Tubulointerstitial Nephritis. J Am Soc Nephrol. 2024." } ], "Validations": [] }

pearls

• While this tool can provide support for the decision to biopsy, it still requires a high index of suspicion.
• Due to the tool’s high negative predictive value, low probability scores can effectively rule out the diagnosis.
• This calculator is not intended to diagnose AIN, but rather to identify the likelihood that a patient may have the disease.
• Note: The initial study suggested that adding urine cytokines (e.g., IL-9, TNF-alpha) could improve probability predictions. However, these are not yet available for clinical use and need further research.

usecase

• Assesses a patient’s risk for acute interstitial nephritis (AIN), guiding decisions about who should undergo a kidney biopsy.
• May be particularly helpful with atypical or subclinical presentations of AIN.

reasons

Quantifies the probability of AIN, aiding in the identification of potentially unrecognized cases. Helps avoid unnecessary risks and complications associated with kidney biopsies in low-risk patients. Early identification of AIN can enable timely intervention to prevent permanent kidney damage.

next_advice

• The original study did not define specific probability cutoffs but suggested:
  • Low probability: AIN is unlikely; evaluate for alternative diagnoses.
  • Intermediate or high probability: AIN is possible; further evaluation with a kidney biopsy is warranted.
• This tool should not be the sole determinant for pursuing a biopsy. Clinical judgment remains crucial.

next_actions

next_management

diseases

[ "Acute Kidney Injury", "Kidney Failure", "Acute Interstitial Nephritis" ]

input_schema

[ { "conditionality": null, "default": null, "fhir_rules": null, "inct": null, "label_en": "<p>Creatinine</p>", "name": "cr", "optional": false, "tips_en": "", "type": "textbox", "unit": "cr" }, { "conditionality": null, "default": null, "fhir_rules": null, "inct": null, "label_en": "<p>BUN</p>", "name": "bun", "optional": false, "tips_en": "", "type": "textbox", "unit": "bun" }, { "conditionality": null, "default": null, "fhir_rules": null, "inct": null, "label_en": "<p>Urine specific gravity</p>", "name": "urgrav", "optional": false, "tips_en": "", "type": "textbox", "unit": "urgrav" }, { "conditionality": null, "default": null, "label_en": "<p>Urine dipstick protein</p>", "mdcalc_info_concept": null, "name": "urprot", "option_fhir_rules": null, "optional": false, "options": [ { "label": "1+ or lower", "value": 0 }, { "label": "2+ or higher", "value": 1 } ], "show_points": false, "tips_en": "", "type": "radio" }, { "conditionality": null, "default": null, "fhir_rules": null, "inct": null, "label_en": "<p>Local prevalence of AIN among all biopsies</p>", "name": "prev", "optional": false, "tips_en": "If unknown, enter 0.23", "type": "textbox", "unit": "ain_prev" } ]

instructions

Should only be used for patients in whom a kidney biopsy is being considered.

published

2024-07-25T16:27:29.015Z

purpose

[ "Diagnosis", "Prognosis" ]

search_terms

[ "Acute Interstitial Nephritis (AIN) Risk Calculator", "AIN Risk Calculator", "AIN", "acute interstitial nephritis", "acute kidney injury", "AKI", "kidney biopsy", "AIN diagnosis", "kidney damage", "urine protein", "BUN", "creatinine", "AIN risk", "acute interstitial nephritis risk" ]

seo

{ "keywords_en": "Acute Interstitial Nephritis (AIN) Risk Calculator, AIN Risk Calculator, AIN, acute interstitial nephritis, acute kidney injury, AKI, kidney biopsy, AIN diagnosis, kidney damage, urine protein, BUN, creatinine, AIN risk, acute interstitial nephritis risk", "meta_description_en": "The Acute Interstitial Nephritis (AIN) Risk Calculator identifies acute interstitial nephritis in the at-risk population." }

specialty

[ "Critical Care", "Emergency Medicine", "Family Practice", "Hospitalist Medicine", "Internal Medicine", "Nephrology", "Primary Care" ]

departments

[ "Genitourinary", "Renal" ]

tags

[]

version_number

1

versions

[]

related

[ { "calcId": 10585, "short_title_en": "CP-AKI", "slug": "cisplatin-associated-acute-kidney-iInjury-cp-aki-risk-calculator" }, { "calcId": 10063, "short_title_en": "Licurse Score", "slug": "licurse-score-renal-ultrasound" }, { "calcId": 10501, "short_title_en": "BUN Creatinine Ratio", "slug": "bun-creatinine-ratio" } ]

ismed

false

section

[ "whenToUseViewed", "pearlsPitfallsViewed", "whyUseViewed", "nextStepsViewed" ]

cleaned_departments

[ "urology", "urology" ]

cleaned_use

[ "Assesses a patient’s risk for acute interstitial nephritis (AIN), guiding decisions about who should undergo a kidney biopsy.", "May be particularly helpful with atypical or subclinical presentations of AIN." ]

pub

false