Test Details
Methodology
Immunologic
Result Turnaround Time
3 - 5 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
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
Special Instructions
The first tube of a routinely obtained three-tube set of cerebrospinal fluid should be used.
Footnotes
Specimen Requirements
Specimen
Cerebrospinal fluid (CSF)
Volume
0.5 mL
Minimum Volume
0.25 mL
Container
Clean sterile tube
Collection Instructions
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.
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | 14 days |
Refrigerated | 14 days |
Frozen | 14 days |
Freeze/thaw cycles | Stable x3 |
Reference Range
See table.
Age | Male (mg/dL) | Female (mg/dL) |
|---|---|---|
0 to 6 m | Not established | Not established |
7 m to 5 y | 5–25 | 5–17 |
6 to 12 y | 5–25 | 7–29 |
13 to 17 y | 7–30 | 7–29 |
18 to 40 y | 10–45 | 7–29 |
41 to 50 y | 10–45 | 8–37 |
51 to 70 y | 15–55 | 8–37 |
>70 y | 15–55 | 10–46 |
Storage Instructions
Room temperature
Causes for Rejection
Excessive blood in CSF
LOINC® Map
| 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 |
| Order Code | 012229 | |||||
| Order Code Name | Albumin, Cerebrospinal Fluid | |||||
| Order Loinc | 1746-7 | |||||
| Result Code | 012230 | |||||
| Result Code Name | Albumin, CSF | |||||
| UofM | mg/dL | |||||
| Result LOINC | 1746-7 |