🧠 CSF WBC Correction (Traumatic LP)
After a traumatic lumbar puncture, the CSF WBC correction removes white cells introduced by admixed blood using the peripheral counts.
CSF WBC Correction (Traumatic LP)
CSF white cells (/μL)
CSF red cells (/μL)
Peripheral blood WBC (×10⁹/L)
Peripheral blood RBC (×10¹²/L)
When to use
Enter CSF white and red cell counts plus peripheral blood WBC and RBC; the tool returns the corrected CSF WBC and the predicted admixed white cells.
How it works
Predicted admixed WBC = CSF RBC × (blood WBC / blood RBC) in matched units; corrected CSF WBC = measured CSF WBC − predicted admixed.
Key points
- A common rule of thumb subtracts roughly 1 WBC per 500–1000 RBC, or uses ~1:700 when the blood count is normal (original synthesis · not guideline verbatim).
- The correction is an estimate; suspected meningitis still rests on glucose/protein, Gram stain, culture, and PCR.
- Differential cytology and a high pretest probability should override a reassuring corrected count.
References
- Greenberg RG, et al. Traumatic lumbar punctures in neonates: test performance of the cerebrospinal fluid white blood cell count. Pediatr Infect Dis J. 2008.
- Mazor SS, et al. Interpretation of traumatic lumbar punctures: who can go home? Pediatrics. 2003.
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.