LRINEC Score Calculator — Necrotizing Fasciitis Risk
Enter six routine laboratory values — CRP, WBC, haemoglobin, serum sodium, creatinine, and glucose — to compute the LRINEC (Laboratory Risk Indicator for Necrotizing Fasciitis) score and stratify the risk of necrotizing fasciitis requiring urgent surgical intervention.
mg/L
×10³/µL
g/dL
mEq/L
mg/dL
mg/dL
Intermediate risk
- 1
CRP points
CRP ≥ 150 mg/L = +4 - 2
WBC points
WBC 15–25 ×10³/µL = +1 - 3
Hgb points
Hgb 11–13.5 g/dL = +1 - 4
Na + creatinine + glucose points
Na(+0) + Cr(+0) + Glu(+0) = +0 - 5
Total LRINEC score
4 + 1 + 1 + 0 = 6
How does this calculator work?
LRINEC adds points for CRP ≥ 150 (+4), elevated WBC (+1–2), low haemoglobin (+1–2), hyponatraemia (+2), elevated creatinine (+2), and hyperglycaemia (+1). Score 0–5 = low risk, 6–7 = intermediate, ≥ 8 = high risk of necrotizing fasciitis. Always combined with clinical assessment — score alone cannot exclude the diagnosis.
Formula
How this is calculated
The LRINEC score was derived by Wong et al. (Critical Care Medicine, 2004) from a retrospective study to distinguish necrotizing fasciitis from severe cellulitis using routine admission blood tests. Each of six laboratory parameters is assigned points based on cut-off values: CRP ≥ 150 mg/L (4 points), WBC 15–25 or >25 ×10³/µL (1 or 2 points), haemoglobin < 11 or 11–13.5 g/dL (2 or 1 points), sodium < 135 mEq/L (2 points), creatinine > 1.6 mg/dL (2 points), and glucose > 180 mg/dL (1 point). The maximum score is 13.
A total score of 0–5 indicates low risk (<50% probability of necrotizing fasciitis). Scores of 6–7 indicate intermediate risk (~50% probability) and should prompt close monitoring and surgical consultation. Scores ≥ 8 indicate high risk (>75% probability) and are a strong indicator for urgent surgical exploration.
Important limitations: the original study had a relatively small sample size and was conducted in a single centre. Subsequent external validation studies have shown lower sensitivity (around 77%) than the original paper reported, meaning a low LRINEC score does not reliably rule out necrotizing fasciitis. Clinical findings — rapidly spreading erythema, crepitus, severe pain out of proportion to exam, haemodynamic instability — should always be the primary driver of the decision to take a patient to theatre. Never rely on the LRINEC score alone.
Frequently asked questions
A score ≥ 6 is the traditional threshold for intermediate-to-high risk, warranting urgent surgical consultation. Many centres use ≥ 6 as the trigger for surgical exploration because of the catastrophic mortality of delayed diagnosis; a score ≥ 8 is widely cited as strongly suggestive of necrotizing fasciitis.
No. Studies have found sensitivities as low as 59–77% for the LRINEC score, meaning a significant proportion of confirmed necrotizing fasciitis cases score below 6. A low score reduces the probability but cannot safely exclude the diagnosis — clinical suspicion must always take precedence.
CRP in mg/L (not mg/dL — note the original paper uses mg/L where the threshold is 150; some local labs report in mg/dL, in which case multiply by 10), WBC in ×10³ per µL (= thousands per mm³), haemoglobin in g/dL, sodium in mEq/L (= mmol/L), creatinine in mg/dL, and glucose in mg/dL. For SI units, convert creatinine (µmol/L ÷ 88.4) and glucose (mmol/L × 18) before entering.
Also known as
TG we-Calculate Editorial Team. (2026). LRINEC Score Calculator — Necrotizing Fasciitis Risk [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/lrinec-score-calculator
TG we-Calculate Editorial Team. "LRINEC Score Calculator — Necrotizing Fasciitis Risk." TG we-Calculate. 2026. https://we-calculate.com/calculator/lrinec-score-calculator.
TG we-Calculate Editorial Team, "LRINEC Score Calculator — Necrotizing Fasciitis Risk," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/lrinec-score-calculator
@misc{wecalculate_lrinec_score_calculator, title = {LRINEC Score Calculator — Necrotizing Fasciitis Risk}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/lrinec-score-calculator}}, year = {2026}, note = {TG we-Calculate} }
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