Unit Converter
Neuron – specific enolase (NSE)
Synonyms
- NSE
- γ-enolase
- Neuron-specific γ-enolase
- Neural enolase
- Neuroendocrine enolase
- Enolase 2 (ENO2)
Units of Measurement
- ng/mL
- ng/dL
- ng/100 mL
- ng%
- ng/L
- µg/L
Molecular Weight
78–82 kDa (dimeric enzyme)
Unit Conversions
Direct Mass Units
1 ng/mL=100 ng/dL1\ \text{ng/mL} = 100\ \text{ng/dL}1 ng/mL=100 ng/dL 1 ng/mL=1 µg/L1\ \text{ng/mL} = 1\ \text{µg/L}1 ng/mL=1 µg/L 1 ng/L=0.001 ng/mL1\ \text{ng/L} = 0.001\ \text{ng/mL}1 ng/L=0.001 ng/mL
ng% / ng/100mL
\text{ng%} = \text{ng/dL} = \frac{\text{ng/mL}}{100}
Description
Neuron-Specific Enolase (NSE) is the neuron- and neuroendocrine-restricted isoenzyme of the glycolytic enzyme enolase. It is present in:
- Neurons
- Neuroendocrine cells
- Neuroblastoma cells
- Small-cell lung carcinoma (SCLC) cells
- Chromaffin cells
NSE is released into blood when:
- Neuroendocrine tumors proliferate
- Neuronal injury occurs
- Cell lysis happens (hemolysis, sample handling errors)
NSE is used as:
- Tumor marker
- Neurological injury marker
- Prognostic indicator after cardiac arrest
Physiological Role
Although an enzyme in glycolysis, NSE in clinical medicine is a biomarker for damaged or proliferating neural/neuroendocrine tissue.
Clinical Significance
HIGH NSE
1. Small-Cell Lung Carcinoma (SCLC)
Most important indication.
- 60–80% of SCLC patients show elevated NSE
- Useful for:
- Diagnosis
- Staging
- Monitoring chemotherapy response
- Detecting relapse
- Diagnosis
2. Neuroblastoma
Used in:
- Diagnosis
- Tumor burden assessment
- Monitoring treatment
3. Other Neuroendocrine Tumors
- Pheochromocytoma
- Medullary thyroid carcinoma
- Pancreatic neuroendocrine tumors
- Carcinoid tumors
4. Neuronal Injury
Raised in:
- Traumatic brain injury (TBI)
- Hypoxic brain injury
- Stroke
- Cardiac arrest (prognostication)
- Seizures
- CNS infections
5. Hemolysis
Red blood cells contain NSE.
→ Even slight hemolysis causes false elevation
(NSE is extremely hemolysis-sensitive)
LOW NSE
Not clinically significant.
Used mainly to confirm:
- Successful tumor response
- Absence of neuronal injury
Reference Intervals
Adults
- < 12.5 ng/mL
Children
- Similar to adults
- Neuroblastoma patients often show markedly elevated levels
Interpretation Thresholds
- < 12.5 ng/mL → Normal
- 12.5–20 ng/mL → Slight elevation (repeat & rule-out hemolysis)
- > 20 ng/mL → Suggestive of neuroendocrine tumor
- > 100 ng/mL → Strongly indicative of aggressive disease
- > 200 ng/mL → High tumor burden or extensive metastatic disease
Diagnostic Uses
1. Small-Cell Lung Carcinoma (SCLC)
- Diagnose
- Monitor chemotherapy response
- Detect relapse (rising NSE precedes imaging changes)
- Prognostic marker
2. Neuroblastoma
- Baseline marker
- Treatment monitoring
- Prognosis assessment
3. Cardiac Arrest Prognostication
In post–cardiac arrest patients cooled with TTM:
- High NSE at 24–72 hours = poor neurological outcome
4. Traumatic Brain Injury & Stroke
Reflects acute neuronal cell damage.
5. Pheochromocytoma & Neuroendocrine Tumors
Additional marker along with chromogranin A, metanephrines.
Analytical Notes
- Most hemolysis-sensitive tumor marker
→ Even minimal hemolysis invalidates results - Preferred sample: serum
- Refrigerate if not processed immediately
- Half-life: 24 hours
- Not specific alone; interpret with clinical and imaging findings
- Useful in serial measurements (trend > single value)
Clinical Pearls
- In SCLC, falling NSE after chemotherapy indicates good response.
- In cardiac arrest patients, NSE > 60–90 ng/mL at 48–72 hrs predicts poor neurologic recovery.
- Always repeat NSE if sample shows hemolysis.
- Neuroblastoma often produces extremely high NSE levels (hundreds to thousands).
- NSE is not recommended as a stand-alone diagnostic test; must be correlated clinically.
Interesting Fact
NSE was first discovered in neurons, but is now known to be highly expressed in neuroendocrine tumors, making it one of the earliest and most important neuro-oncology biomarkers.
References
- Tietz Clinical Chemistry & Molecular Diagnostics, 8th Edition - Tumor Markers
- NCCN Guidelines - Small Cell Lung Cancer
- Mayo Clinic Laboratories - NSE
- ARUP Consult - Neuroendocrine Tumor Markers
- AHA/Neurology Guidelines - Post–Cardiac Arrest Prognostication
- MedlinePlus / NIH — NSE Test