Neuron-Specific Enolase (NSE) Unit Converter
Neuron-Specific Enolase (NSE) Unit Converter
ng/mL and µg/L are the same number for NSE. The point that matters more than the arithmetic is pre-analytical: red cells contain enolase, so a haemolysed sample gives a falsely high result and cannot be interpreted at all.
Neuron-Specific Enolase (NSE) converter
Mass ladder onlyNeuron-specific enolase 11.4 ng/mL in a non-haemolysed sample
Formula and conversion factors
pg/mL = ng/mL × 1000
- ng/mL = µg/L
- a nanogram per millilitre and a microgram per litre are the same concentration, so nothing is calculated between them
- no molar unit
- NSE is the gamma-gamma dimer of enolase, around 78 kDa, but it is calibrated against an assay standard and no clinical threshold anywhere is written in molar units
- haemolysis
- erythrocytes and platelets contain enolase, so free haemoglobin in the sample raises the measured NSE artefactually. Laboratories reject haemolysed samples outright
- assay dependence
- cut-offs are manufacturer-specific; follow a patient on one platform, since a change of laboratory can move the number with no change in the patient
Worked example
Neuron-specific enolase 11.4 ng/mL in a non-haemolysed sample
11.4 ng/mL = 11.4 µg/L — the two units are identical
11.4 × 1000 = 11,400 pg/mL
No band is shown: the cut-off printed on your own report is the one that applies
If the sample was haemolysed, the number is uninterpretable whatever it says
The three units
| Unit | Relationship | Example |
|---|---|---|
| ng/mL | The usual reporting convention | 11.4 |
| µg/L | Identical to ng/mL | 11.4 |
| pg/mL | ng/mL × 1000 | 11,400 |
Where NSE is used, and the trap that invalidates it
| Setting | Note |
|---|---|
| Small-cell lung cancer | Raised in the majority of cases; used for prognosis and for following response or relapse alongside imaging, not for diagnosis |
| Neuroblastoma | Used in children as one of several markers in assessment and follow-up |
| After cardiac arrest | A prognostic marker in comatose survivors, measured serially at 24, 48 and 72 hours and interpreted only within a multimodal assessment |
| Haemolysed sample | Uninterpretable. Erythrocytes contain enolase, so free haemoglobin raises the result artefactually; Mayo Clinic Laboratories reject any degree of haemolysis, noting free haemoglobin as low as 20 mg/dL can affect the assay |
| Delayed separation | Blood left in contact with cells before centrifugation lets NSE leak from platelets and red cells, so the sample must be spun promptly and not sent through a pneumatic tube first |
| Indicative reference figure | Mayo Clinic Laboratories quote ≤15 ng/mL on the BRAHMS Kryptor assay. That is one platform’s figure, not a universal limit |
Why the sample matters more than the number
NSE is reported in ng/mL or in the identical µg/L, with pg/mL a thousand times larger, so the unit conversion on this page is trivial. The measured species is the gamma-gamma dimer of the glycolytic enzyme enolase, found in neurones and in cells of neuroendocrine origin. It has a molecular mass of roughly 78 kDa, but it is calibrated against an assay standard and no clinical threshold is expressed in molar units, so no molar column is offered.
The single most important thing about an NSE result is the state of the sample it came from. Enolase is present in red cells and in platelets as well as in neurones, so any haemolysis releases it into the serum and raises the measured concentration artefactually. Laboratories reject haemolysed samples for this reason — Mayo Clinic Laboratories reject haemolysis at any level, noting that free haemoglobin as low as 20 mg/dL can affect the result. Delay matters too: blood must be separated promptly, and a specimen left standing or shot through a pneumatic tube before centrifugation can read falsely high. If the report carries a haemolysis comment, the number is not interpretable and the test needs repeating on a fresh sample.
Clinically NSE has two quite separate lives. In oncology it is the marker of neuroendocrine tumours, above all small-cell lung cancer, where it is raised in most patients and is used for prognosis and for following response and relapse alongside imaging, and it is also used in neuroblastoma in children. In critical care it is something else entirely: a prognostic marker in comatose survivors of cardiac arrest, measured serially and interpreted only as one strand of a multimodal assessment, never alone.
No reference band is printed here. The commonly quoted figures, such as the 15 ng/mL upper limit Mayo Clinic Laboratories give for the BRAHMS Kryptor assay, belong to individual platforms and are not interchangeable, so the interval on your own report is the one that applies to your result. For the same reason serial monitoring is only valid on a single assay. Tumour markers are interpreted in context by a clinician; they are not diagnostic on their own.
Frequently asked questions
Is ng/mL the same as µg/L for NSE?
Yes, they are the same number. Only pg/mL differs, being a thousand times larger, so 11.4 ng/mL is 11.4 µg/L and 11,400 pg/mL. No molar unit is used clinically for NSE, so none is offered here.
Why does haemolysis ruin an NSE result?
Because enolase is present in red cells and platelets as well as in neurones. When red cells break down, either in the patient or in the tube, the released enzyme adds to the measured NSE and pushes the result up artefactually. Laboratories reject haemolysed samples rather than report a number that cannot be interpreted.
Does the sample need handling in a particular way?
Yes. It must be centrifuged and separated promptly, because NSE leaks from platelets and red cells while blood stands in contact with them. Some laboratories also ask that the sample is not sent by pneumatic tube before centrifugation, since the mechanical stress alone can cause haemolysis.
What is NSE used for?
In oncology it is a marker of neuroendocrine tumours, principally small-cell lung cancer, and it is used in neuroblastoma in children. Separately, it is used as a prognostic marker in comatose survivors of cardiac arrest, where it is measured serially and read only as part of a multimodal assessment.
What is a normal NSE?
There is no universal figure. Mayo Clinic Laboratories quote ≤15 ng/mL for the BRAHMS Kryptor assay, but cut-offs are manufacturer-specific and are not interchangeable, so the interval printed on your own report is the one to use. A result should be read by a clinician alongside the clinical picture.
Related calculators
References
- Mayo Clinic Laboratories. Neuron-Specific Enolase, Serum (test 80913): reference value ≤15 ng/mL; specimens showing haemolysis at any level are rejected because erythrocytes contain NSE.
- Nolan JP, Sandroni C, Böttiger BW, et al. European Resuscitation Council and European Society of Intensive Care Medicine guidelines 2021: post-resuscitation care. Resuscitation. 2021;161:220–269.
- Isgrò MA, Bottoni P, Scatena R. Neuron-specific enolase as a biomarker: biochemical and clinical aspects. Adv Exp Med Biol. 2015;867:125–143.
Medical Disclaimer: The tools and content provided here are for educational and reference purposes only. They are not intended to substitute for professional medical advice, diagnosis, or treatment. Clinical decisions should always be based on the comprehensive assessment of a qualified healthcare professional.