🦠 LRINEC Score Calculator

The LRINEC score estimates the risk that a soft tissue infection is necrotizing fasciitis, the rapidly destructive "flesh-eating" infection where hours matter. It scores six routine labs: CRP, white cell count, hemoglobin, sodium, creatinine, and glucose, for a total of 0 to 13. Scores of 6 to 7 mean intermediate risk and 8 or above means high risk.

Wong and colleagues derived it in 2004 from patients with necrotizing versus non-necrotizing infections. Enter the six labs and the calculator assigns points per the published cutoffs and names the risk band. It is an adjunct to surgical judgment, never a substitute: a low score with a terrible exam still goes to the operating room.

How to Use This Calculator

Enter the six lab values in standard units: CRP in mg/L, WBC in x10^9/L, hemoglobin in g/dL, sodium in mmol/L, creatinine in mg/dL, glucose in mg/dL. Read the total and the band. Intermediate or high scores in a patient with pain out of proportion, rapidly spreading erythema, or bullae should prompt urgent surgical consultation.

The Six Labs and Their Points

Each cutoff was chosen because it separated necrotizing from non-necrotizing infections in the derivation cohort. CRP dominates with 4 points because severe bacterial invasion drives it sky-high. Hyponatremia and acute kidney injury reflect third-spacing and toxin-mediated organ stress. Hyperglycemia marks both diabetic susceptibility and stress response. The score's published performance was strong in derivation (high sensitivity at >=6), though later external validations found more modest accuracy, which is exactly why guidelines position it as one input to the surgical decision rather than a rule-out test.

Worked Example

CRP 180, WBC 18, Hb 12, Na 132, creatinine 1.4, glucose 200: the points add to 9 / 13, landing in the High risk (>=8) band. CRP alone contributes 4 of those points, which is why a very high CRP with a painful, swollen limb gets surgical attention fast. Drop CRP to 80 and the score falls to 4, low risk.

Reading the Bands

Five or below is low risk, but low does not mean zero: early necrotizing infection can present before labs declare themselves. Six to 7 is intermediate and deserves senior review, serial exams, and a low threshold for imaging or surgical exploration. Eight and above is high risk and should trigger urgent surgical consultation in most protocols. The exam findings that matter most are pain out of proportion to appearance, rapid spread, dusky or bullous skin, and crepitus; any of those can justify surgery with a low score.

When in Doubt, Call Surgery

Necrotizing fasciitis kills quickly and the only definitive test is surgical exploration. This score must never delay a surgical consult when the exam is concerning. If you are a patient with rapidly worsening limb pain, swelling, fever, or dusky skin, go to the emergency department immediately and say you are worried about necrotizing infection. For informational purposes only, not medical advice. Consult a healthcare professional.

Related tools: Light's criteria, MEWS score and Morse fall scale.

For informational purposes only, not medical advice. Consult a healthcare professional.