Modified NIH Activity and Chronicity Indices (Lupus Nephritis)

The MODIFIED NIH ACTIVITY AND CHRONICITY INDICES for lupus nephritis, from the 2018 ISN/RPS revision (Bajema and colleagues, Kidney Int 2018).

Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.

Example

ACTIVITY index. Endocapillary hypercellularity
2
ACTIVITY index. Neutrophils and/or karyorrhexis
1
ACTIVITY index. Fibrinoid necrosis
1
ACTIVITY index. Hyaline deposits
2
ACTIVITY index. Cellular and/or fibrocellular crescents
1
ACTIVITY index. Interstitial inflammation
1
CHRONICITY index. Total glomerulosclerosis
1
CHRONICITY index. Fibrous crescents
0
CHRONICITY index. Tubular atrophy
1
CHRONICITY index. Interstitial fibrosis
1

Result: activity index 10 of 24 and chronicity index 3 of 12.

The tool opens with these values already filled in. Replace them with your own.

What the result means

Purpose
Introduced by the 2018 revision to REPLACE the A / A-C / C subscripts on classes III and IV.
Two indices
Activity 0-24 and chronicity 0-12. NEVER added together: they measure opposite things.
Why 24
Six components at 0-3 would cap at 18. The extra 6 is entirely the two doubled terms.
Two rubrics
Glomerular = percent of glomeruli. Interstitial = mild/moderate/severe. Same range, different question.
Not 1984
Karyorrhexis moved from fibrinoid necrosis to neutrophils, so old and new scores are not comparable.
Scope
Histology only. Does not assign the ISN/RPS class, measure function, or indicate immunosuppression.

What you enter

  • ACTIVITY index.
  • ACTIVITY index.
  • ACTIVITY index.
  • ACTIVITY index.
  • ACTIVITY index.
  • ACTIVITY index.
  • CHRONICITY index.
  • CHRONICITY index.
  • CHRONICITY index.
  • CHRONICITY index.
Full field descriptions
  • ACTIVITY index. Endocapillary hypercellularity. Weight x1. Rubric: 0 = Not present; 1 = Under 25 percent of glomeruli; 2 = 25 to 50 percent of glomeruli; 3 = Over 50 percent of glomeruli
  • ACTIVITY index. Neutrophils and/or karyorrhexis. Weight x1. Rubric: 0 = Not present; 1 = Under 25 percent of glomeruli; 2 = 25 to 50 percent of glomeruli; 3 = Over 50 percent of glomeruli
  • ACTIVITY index. Fibrinoid necrosis. Weight x2. Rubric: 0 = Not present; 1 = Under 25 percent of glomeruli; 2 = 25 to 50 percent of glomeruli; 3 = Over 50 percent of glomeruli
  • ACTIVITY index. Hyaline deposits (wire loops and/or hyaline thrombi). Weight x1. Rubric: 0 = Not present; 1 = Under 25 percent of glomeruli; 2 = 25 to 50 percent of glomeruli; 3 = Over 50 percent of glomeruli
  • ACTIVITY index. Cellular and/or fibrocellular crescents. Weight x2. Rubric: 0 = Not present; 1 = Under 25 percent of glomeruli; 2 = 25 to 50 percent of glomeruli; 3 = Over 50 percent of glomeruli
  • ACTIVITY index. Interstitial inflammation. Weight x1. Rubric: 0 = Not present; 1 = Mild; 2 = Moderate; 3 = Severe
  • CHRONICITY index. Total glomerulosclerosis (global AND segmental). Weight x1. Rubric: 0 = Not present; 1 = Under 25 percent of glomeruli; 2 = 25 to 50 percent of glomeruli; 3 = Over 50 percent of glomeruli
  • CHRONICITY index. Fibrous crescents. Weight x1. Rubric: 0 = Not present; 1 = Under 25 percent of glomeruli; 2 = 25 to 50 percent of glomeruli; 3 = Over 50 percent of glomeruli
  • CHRONICITY index. Tubular atrophy. Weight x1. Rubric: 0 = Not present; 1 = Mild; 2 = Moderate; 3 = Severe
  • CHRONICITY index. Interstitial fibrosis. Weight x1. Rubric: 0 = Not present; 1 = Mild; 2 = Moderate; 3 = Severe
How this is calculated
Weights
ONLY fibrinoid necrosis and cellular/fibrocellular crescents are x2, and only in activity. Chronicity is unweighted.
Denominator
Percent of glomeruli IN THE SAMPLE, so an inadequate biopsy can only LOWER the score.

Citation

Bajema IM, Wilhelmus S, Alpers CE, et al. Revision of the International Society of Nephrology/Renal Pathology Society classification for lupus nephritis: clarification of definitions, and modified National Institutes of Health activity and chronicity indices. Kidney Int. 2018;93(4):789-796. Read the source ↗

A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.

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Built by Clay Good. Source on GitHub.