Albumin, Cerebrospinal Fluid

CPT: 82042
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Test Details


  • Cerebrospinal Fluid Albumin
  • CSF Albumin


The degree of permeability of the blood-brain barrier can be evaluated by the quantitative measurements of albumin in the CSF and the serum on specimens obtained at the same time. Albumin is a particularly suitable indicator of protein because it is neither synthesized nor metabolized intrathecally. In CSF that is free of blood contamination, therefore, albumin must necessarily have come from plasma through the blood-brain barrier.

Using the results of quantitative CSF and serum albumin assays, a CSF (in mg/dL)/serum (in g/dL) albumin index can be calculated. An index value <9 is considered consistent with an intact barrier. Values of 9-14 are interpreted as slight impairment, 14−30 as moderate impairment, and 30−100 as severe impairment. Values >100 indicate complete breakdown of the barrier.1



Reference Interval

11−48 mg/dL

Specimen Requirements


Cerebrospinal fluid (CSF)


0.5 mL

Minimum Volume

0.25 mL


Clean sterile tube


A CSF specimen is obtained by spinal tap and should be collected in sterile tubes and submitted to the laboratory as soon as possible. Ordinarily, three samples are collected in sterile tubes, labeled sequentially as N° 1 (chemistry and immunology studies), N° 2 (microbiological examination), and N° 3 (cell count and differential). Tubes must be labeled with the patient's full name, date, time of collection, and with the number indicating the sequence in which the tubes were obtained.

Storage Instructions

Room temperature

Stability Requirements



Room temperature

14 days


14 days


14 days

Freeze/thaw cycles

Stable x3

Causes for Rejection

Excessive blood in CSF

Clinical Information

Special Instructions

The first tube of a routinely obtained three-tube set of cerebrospinal fluid should be used.


1. Schliep G, Felgenhauer K. Serum-CSF protein gradients, the blood-GSF barrier and the local immune response. J Neurol. 1978 May 18; 218(2):77-96.78976


Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
012229 Albumin, Cerebrospinal Fluid 1746-7 012230 Albumin, CSF mg/dL 1746-7

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