Blood contamination in CSF. Background
Analysis of cells in cerebrospinal fluid (CSF) is an important clinical procedure for diagnosis of a variety of disease. Elevated number and percentage of white blood cells (WBC) in CSF are observed meningitis and other neurological disorders.
The most commonly procedure for collection of CSF is the Lumbar Puncture also known as a spinal tap, which consist of a needle insertion into the spinal canal most commonly to collect CSF for diagnostic testing.
With relative frequency LP procedure is complicated by the contamination of CSF with blood cells as result of needle trauma, also known as traumatic tap. The presence of blood cells and the concentration affected of some substances due to blood contamination in CSF can complicate the analysis and confounding the diagnosis.
Despite CSF is a crystal clear, It is difficult to judge the degree of contamination by visual inspection alone as the visual threshold for perception of blood in the CSF varied from 400 to 6000 red blood cells per mm3 depending on the authors, even visibly undetectable contamination by blood drastically altered the content of CSF.
Diagnostic analysis of CSF can accurately detect certain conditions and diseases, which can otherwise be difficult to diagnose, such as infectious diseases such as meningitis and encephalitis, autoimmune disorders or primary neoplasms located within the central nervous system (meningiomas, asstrocytomas, etc.) or secondary tumors (malignant lymphoma) that infiltrates or metastasize the central nervous system, which is an important adverse complication occurring in patients with B and T cell lymphomas and acute leukemias of lymphoid and myeloid origin. Making the diagnosis of secondary CNS involvement in lymphoma can be difficult due to unspecific signs and symptoms, in this sense, since last year flow cytomentry is playing an important role improving significantly the sensitivity of cytology and imaging identification of leptomeningeal disease in malignant lymphoma at higher risk of CNS disease, particularly in paucicellular samples (1, 2)
As it mentioned above, evaluation of CSF contamination with blood should be performed in all cases where the presence of blood cells (eg, red blood cells and neutrophils), especially when there is expression in peripheral blood of systemic lymphoma (3,4).
The current methods for the determination of contamination in CSF consist of applying corrective formulas based on the assumption that the ratio of WBCs to RBCs in CSF will be identical to that in blood (9). Therefore, this determination is only correct if neither WBC nor red blood cells are lysed in the CSF during the time between collection of the liquid and the cell count, which is very unusual.
In this sense a new method for evaluation of CSF contamination, that allow bypassing these disadvantages, would help to interpret diagnostic results.