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Test ID NSE Neuron-Specific Enolase, Serum


Specimen Required


Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


Secondary ID

80913

Useful For

A follow-up marker in patients with neuron-specific enolase-secreting tumors of any type

 

An auxiliary test in the diagnosis of small cell lung carcinoma

 

An auxiliary test in the diagnosis of carcinoids, islet cell tumors, and neuroblastomas

 

An auxiliary tool in the assessment of comatose patients

Method Name

Homogeneous Time-Resolved Fluorescence

Reporting Name

Neuron Specific Enolase, S

Specimen Type

Serum

Specimen Minimum Volume

0.3 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Refrigerated (preferred) 7 days
  Ambient  5 days

Clinical Information

Enolase is a glycolytic enzyme that catalyzes the conversion of 2-phosphoglycerate to phosphoenolpyruvate. Enolase exists in the form of several tissue-specific isoenzymes, consisting of homo or heterodimers of 3 different monomer-isoforms (alpha, beta, and gamma). Neuron-specific enolase (NSE) is a 78 kDa gamma-homodimer and represents the dominant enolase-isoenzyme found in neuronal and neuroendocrine tissues. Its levels in other tissues, except erythrocytes, are negligible. The biological half-life of NSE in body fluids is approximately 24 hours.

 

Due to this organ-specificity, concentrations of NSE in serum or, more commonly, cerebrospinal fluid (CSF) are often elevated in diseases that result in relative rapid (hours/days to weeks rather than months to years) neuronal destruction. Measurement of NSE in serum or CSF can therefore assist in the differential diagnosis of a variety of neuron-destructive and neurodegenerative disorders. The most common application is in the differential diagnosis of dementias, where elevated CSF concentrations support the diagnosis of rapidly progressive dementias, such as Creutzfeldt-Jacob Disease. NSE may also have utility as a prognostic marker in neuronal injury. For example, there is increasing evidence that elevated serum NSE levels correlate with a poor outcome in coma, particularly when caused by hypoxic insult.

 

NSE is frequently overexpressed by neural crest-derived tumors. Up to 70% of patients with small cell lung carcinoma (SCLC) have elevated serum NSE concentrations at diagnosis. Approximately 90% of patients with advanced SCLC will have serum levels above the healthy reference range. Other neuroendocrine tumors with frequent expression of NSE include carcinoids (up to 66% of cases), islet cell tumors (typically <40% of cases), and neuroblastoma (exact frequency of NSE expression unknown). NSE levels in NSE-secreting neoplasms correlate with tumor mass and tumor metabolic activity. High levels have, therefore, some negative prognostic value. Falling or rising levels are often correlated with tumor shrinkage or recurrence, respectively.

Reference Values

≤15 ng/mL

Serum markers are not specific for malignancy, and values may vary by method.

Cautions

All neuron-specific enolase (NSE) test results must be considered in the clinical context, and interferences or artifactual elevations should be suspected if the clinical NSE test results are at odds with the clinical picture or other tests. The laboratory should be contacted for assistance in these situations.

 

Hemolysis can lead to significant artifactual NSE elevations since erythrocytes contain NSE.

 

Hemoglobin concentrations as low as 20 mg/dL were found to have an adverse effect on NSE testing.

 

Proton pump inhibitor treatment, hemolytic anemia, hepatic failure, and end-stage kidney failure can also result in artifactual NSE elevations.

 

Other false-positive results depend on the treating context. When performing NSE testing for tumor diagnosis or follow-up, epileptic seizure, brain injury, encephalitis, stroke, and rapidly progressive dementia might result in false-positive results. On the other hand, when NSE testing is performed to assist in neurological diagnosis, NSE-secreting tumors can represent a source of false-positive results.

 

NSE values can vary significantly between methods/assays. Serial follow-up should be performed with the same assay. If assays are changed, patients should have their baseline level reestablished. This assay is an immunometric assay and can, in rare situations, be affected by false-low results in the presence of extremely high NSE concentrations ("hooking") or autoantibodies to NSE.

 

In rare cases, some individuals can develop antibodies to mouse or other animal antibodies (often referred to as human anti-mouse antibodies [HAMA] or heterophile antibodies), which may cause interference in some immunoassays. Caution should be used in interpretation of results, and the laboratory should be alerted if the result does not correlate with the clinical presentation.

Day(s) Performed

Monday through Saturday

Report Available

1 to 3 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

83520

NY State Approved

Yes