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LRINEC score

Laboratory risk indicator for necrotising fasciitis in severe soft-tissue infection

Sources last checked: 2026-11-03

LRINEC score

Laboratory risk indicator for necrotising fasciitis in severe soft-tissue infection

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Derived retrospectively in Singapore. Later studies and a 2019 meta-analysis found poor sensitivity: LRINEC should not be used to rule out necrotising fasciitis. Clinical suspicion (pain out of proportion, rapid progression, systemic toxicity) warrants early surgical assessment regardless of the score.

Source: Wong CH, Khin LW, Heng KS et al. The LRINEC (Laboratory Risk Indicator for Necrotizing Fasciitis) score: a tool for distinguishing necrotizing fasciitis from other soft tissue infections. Crit Care Med 2004;32(7):1535-1541. Point table as reproduced in Syed A et al., Malays Orthop J 2017 (Table I).Open

Interpretation

Low risk (≤ 5)Low-risk category of the original score. A low score does not exclude necrotising fasciitis: in a 2019 meta-analysis LRINEC ≥ 6 had a pooled sensitivity of only 68.2 %.
Intermediate risk (6–7)Wong 2004: patients with a score ≥ 6 should be carefully evaluated for necrotising fasciitis (PPV 92 %, NPV 96 % in the derivation).
High risk (≥ 8)High-risk category of the original score. Pooled specificity of LRINEC ≥ 8 was 94.9 % (sensitivity 40.8 %) in the 2019 meta-analysis.

What is the LRINEC score?

The LRINEC (Laboratory Risk Indicator for Necrotizing Fasciitis) score combines six routine blood tests — CRP, white cell count, haemoglobin, sodium, creatinine and glucose — into a 0–13 point score. Wong and colleagues derived it retrospectively in Singapore from 89 patients with necrotising fasciitis and 225 controls with severe cellulitis or abscess (Crit Care Med 2004), proposing ≥ 6 as the cut-off. Later studies found its sensitivity much lower than originally reported.

When to use it

  • Adults with a severe soft-tissue infection where necrotising fasciitis is a concern.
  • Adding objective laboratory weight to the clinical picture when discussing surgical exploration.
  • Documenting a structured assessment in suspected necrotising soft-tissue infection.

When not to use it

  • To rule out necrotising fasciitis — a 2019 meta-analysis found 68 % sensitivity at ≥ 6.
  • When clinical signs already make the diagnosis likely (crepitus, skin necrosis, rapid spread, shock) — surgical assessment should not wait for a score.
  • When one of the six values is missing — the score is only valid with all six.

How it is calculated

CRP ≥ 150 mg/L → 4 WBC 15–25 × 10⁹/L → 1; > 25 → 2 Haemoglobin 11–13.5 g/dL → 1; < 11 → 2 Sodium < 135 mmol/L → 2 Creatinine > 141 µmol/L → 2 Glucose > 10 mmol/L → 1 Range 0–13.

Clinical pearls and limitations

  • Derived retrospectively in Singapore. Later studies and a 2019 meta-analysis found poor sensitivity: LRINEC should not be used to rule out necrotising fasciitis. Clinical suspicion (pain out of proportion, rapid progression, systemic toxicity) warrants early surgical assessment regardless of the score.
  • CRP carries most weight: ≥ 150 mg/L alone gives 4 points.
  • In a 2017 US emergency-department study 63.8 % of patients with confirmed necrotising fasciitis scored in the low-risk band.
  • At ≥ 8 the score is fairly specific (94.9 % pooled), so a high score supports, but a low score does not refute, the diagnosis.
  • Creatinine and glucose thresholds are in SI units (141 µmol/L, 10 mmol/L); haemoglobin is defined in g/dL.

Frequently asked questions

How is the LRINEC score calculated?

CRP ≥ 150 mg/L 4 points; WBC 15–25 × 10⁹/L 1, > 25 2; haemoglobin 11–13.5 g/dL 1, < 11 2; sodium < 135 mmol/L 2; creatinine > 141 µmol/L 2; glucose > 10 mmol/L 1.

What LRINEC score suggests necrotising fasciitis?

The original paper recommended careful evaluation at ≥ 6; ≤ 5 is low, 6–7 intermediate and ≥ 8 high risk.

Can a low LRINEC score rule out necrotising fasciitis?

No. Pooled sensitivity at ≥ 6 was 68.2 % in a 2019 meta-analysis, so roughly a third of cases score below the cut-off.

Is the LRINEC score still recommended?

It remains in use as an adjunct, but systematic reviews conclude it should not be used to exclude necrotising soft-tissue infection; clinical suspicion should prompt early surgical consultation.

Evidence and guidelines

  1. Primary source: Wong CH, Khin LW, Heng KS et al. The LRINEC (Laboratory Risk Indicator for Necrotizing Fasciitis) score: a tool for distinguishing necrotizing fasciitis from other soft tissue infections. Crit Care Med 2004;32(7):1535-1541. Point table as reproduced in Syed A et al., Malays Orthop J 2017 (Table I).
  2. Syed A, Alvin T, Fazrina A, Abdul R. Determining if positive predictive value using Laboratory Risk Indicator for Necrotising Fasciitis is applicable in Malaysian patients with necrotising fasciitis. Malays Orthop J 2017;11(2):36-39 — Table I reproduces the LRINEC point table.
  3. Neeki MM, Dong F, Au C et al. Evaluating the Laboratory Risk Indicator to differentiate cellulitis from necrotizing fasciitis in the emergency department. West J Emerg Med 2017;18(4):684-689 — risk categories ≤ 5 / 6–7 / ≥ 8.
  4. Fernando SM, Tran A, Cheng W et al. Necrotizing soft tissue infection: diagnostic accuracy of physical examination, imaging, and LRINEC score: a systematic review and meta-analysis. Ann Surg 2019;269(1):58-65.

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