What are the typical erythrocyte sedimentation rate (ESR) and C‑reactive protein (CRP) levels in patients with typhoid fever?

ESR and CRP in Typhoid Fever

In typhoid fever, CRP is typically elevated (geometric mean ~43 mg/L in culture-positive cases) and is more useful than ESR for diagnosis, though both have limited sensitivity and specificity as standalone tests. 1

Typical Laboratory Values in Typhoid

C-Reactive Protein (CRP)

• Culture-positive typhoid patients: Geometric mean of 43 mg/L (range 12-150 mg/L) 1
• Clinically diagnosed typhoid (culture-negative): Geometric mean of 26 mg/L (range 8-85 mg/L) 1
• CRP levels correlate with Widal O and H agglutinin titers, reflecting the immune response to infection 1
• CRP rises 12-24 hours after infection onset, peaking at 48 hours 2

Erythrocyte Sedimentation Rate (ESR)

• While ESR data specific to typhoid is limited in the provided evidence, general bacterial infections show ESR elevation
• ESR is less specific than CRP for acute bacterial infections 3
• ESR rises more slowly than CRP and is affected by age, anemia, and other factors 4, 5

Diagnostic Performance

At a CRP cut-off of 30 mg/L for typhoid fever:

• Sensitivity: 68%
• Specificity: 58%
• Area under ROC curve: 0.65 1

These values indicate moderate diagnostic utility - CRP is elevated in typhoid but overlaps significantly with other febrile illnesses, limiting its use as a primary diagnostic test.

Clinical Application Algorithm

1. Suspect typhoid based on clinical presentation (prolonged fever, typical symptoms)
2. Obtain blood cultures (gold standard) plus CRP
3. Interpret CRP results:
   • CRP >43 mg/L: Supports typhoid diagnosis in appropriate clinical context
   • CRP 26-43 mg/L: Intermediate probability
   • CRP <26 mg/L: Lower probability but does not exclude typhoid
4. Use CRP as adjunctive data, not standalone diagnostic criterion
5. Serial CRP measurements may help monitor treatment response, as CRP decreases rapidly with effective antibiotic therapy 2

Important Caveats

• CRP has limited discriminatory power between typhoid and other bacterial infections 1
• Age and fever duration independently affect CRP levels 1
• Normal CRP does NOT exclude typhoid - sensitivity is only 68% 1
• CRP is more useful for monitoring treatment response than initial diagnosis 4
• In typhoid-endemic areas, elevated CRP should be interpreted alongside clinical features, blood cultures, and epidemiological context 1

Bottom line: Use CRP as one component of clinical assessment rather than relying on it for definitive diagnosis. Blood culture remains the diagnostic gold standard for typhoid fever.