26553 Beta-2 Transferrin: Detection of Spinal Fluid in Other Body Fluid (BETA2)

​​B2 Transferrin; Cerebrospinal Fluid Leakage; CSF Specific Transferrin; Otorrhea, Spinal Fluid; Rhinorrhea, Spinal Fluid; Tau Protein; Transferrin B2; Transferrin, Spinal Fluid​

​​Detection of spinal fluid in body fluids, such as ear or nasal fluid

​Additional Testing Requirements: If specimens are collected from multiple sites on the body (ie, left and right), each specimen must be sent under a separate order. 

Necessary Information: Indicate specimen source. Include whether the source is from the right or left side of the body, if applicable. 

Collection Instructions: 

1. If submitting a syringe, remove needle. Add cap to end of syringe.

2. If direct collection is not feasible, specimen may be collected using a plain cotton swab or gauze.​

3. If gauze is used to collect specimen, circle area on the gauze where specimen was collected.

4. Place cotton swab or gauze in as small of a container as possible (eg, plain test tube or collection container). 

5. Do not collect specimen with a culture swab.

6. Do not add any liquid to the swab or gauze.

Additional Information: 

1. Specimens collected from above the shoulders risk salivary contamination, which can degrade the beta-2 transferrin protein. These specimens should be frozen immediately following collection and kept frozen until testing is performed. 

2. Although results may be obtainable on smaller specimens (perhaps as little as 0.05 mL, depending on the protein concentrations and percentage of spinal fluid in the specimen), reliable results are best obtained with an adequate specimen volume.

3. Specimens collected with additives such as microbiology media (eg, Stuart or Amies liquid medium) or TransFix/EDTA (used for analyses in flow cytometry) yield uninterpretable results and will be rejected. 

​Be​ta-2 transferrin is also found in aqueous humor and in serum of patients with rare metabolic glycoprotein disorders or genetic variatns of transferrin.

Specimens stored in storage tubes with TransFix/ EDTA (used for analyses in flow cytometry) are not acceptable. The contact of cerebrospinal fluid with the stabilization solution contained in these tubes changes the migration and the results cannot be interpreted. 

​The diagnosis of cerebrospinal fluid (CSF) rhinorrhea or otorrhea (leakage of CSF into the nose or ear canal, usually as a result of head trauma, tumor, congenital malformation, or surgery) is often difficult to confirm. Traditional chemical analyses (eg, glucose, protein, specific gravity) are unreliable. Radiographic studies, especially those involving the injection of dyes or radiographic compounds, are costly and may introduce additional risks to the patient.​

Transferrin that migrates in the beta-1 electrophoretic fraction (beta-1 transferrin) is found in most body fluids. Beta-2 transferrin is a CSF-specific variant of transferrin and is used as an endogenous marker of CSF leakage. Beta-2 transferrin is formed by loss of sialic acid due to the presence of neuraminidase in the central nervous system. Beta-2 transferrin has also been called CSF-specific transferrin and tau protein.

Prompt diagnosis and localization facilitates appropriate decisions and decreases the risk of meningitis.

​The ​cerebrospinal fluid (CSF) variant of transferrin is identified by its unique electrophoretic migration. If beta-1 and beta-2 transferrin are detected in drainage fluids, the specimen is presumed to be contaminated with CSF.

The presence of beta-2 transferrin band is detectable with as little as 2.5% spinal fluid contamination of body fluid.​