Exploring the impact of pre-analytical processes on the determination of neuron-specific enolase in serum samples.

Objective: To explore pre-analysis factors affecting the results of neuron-specific enolase (NSE) testing of serum samples, select optimal testing conditions, and reduce the false-positive rate of NSE.

Methods: Serum NSE levels were measured using the Roche e801 electrochemiluminescence immunoassay in healthy participants who underwent physical examinations at the Fourth Affiliated Hospital of Soochow University from September 2022 to December 2024, including both outpatients and hospitalized patients. Further, we analyzed the effects of various pre-analytical factors on the NSE positivity rate (NSE>16.3 ng/mL was judged to be NSE-positive) and the proportion of hemolysis index (H) ≥13 (H = 13 was equivalent to hemoglobin concentration of 13 mg/dl).

Results: This study found that the positive rate of NSE and the H ≥ 13 proportion were influenced by factors such as hemolysis, the method of sample transportation, pre-centrifugation storage time, the brand of blood collection tube, and centrifugation conditions. However, post-centrifugation storage time had little effect on these results.

Conclusion: After blood collection, the NSE positive rate and the H ≥ 13 proportion significantly decreased using a gentler transportation method, such as a box logistics or manual transport, centrifuging within 30-40 min or no longer than 1 h at the latest post-collection, and centrifuging at 2100  (acceleration 4, deceleration 6) and 20 °C for 10 min with brand B blood collection tubes. Under these conditions, there was no significant impact on NSE results for males with H < 6 and females with H < 5.