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Serum neuron specific enolase - impact of storage and measuring method.

Rundgren M, Cronberg T, Friberg H, Isaksson A - BMC Res Notes (2014)

Bottom Line: The paired NSE results in original and stored samples were not significantly different, using the LNSE-method.The CNSE method resulted in 36% higher values on average.In the method comparison on fresh samples, the CNSE-method generated on average 15% higher values compared to the LNSE-method, and the difference between the paired results was significant (p < 0.0001).

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Sciences, Division of Anaesthesia and Intensive Care, Lund University, Lund, Sweden. malin.rundgren@skane.se.

ABSTRACT

Background: Neuron specific enolase (NSE) is a recognized biomarker for assessment of neurological outcome after cardiac arrest, but its reliability has been questioned. Our aim was to investigate what influence storage of samples and choice of measuring methods may have on levels of NSE in peripheral blood.

Methods: Two serum samples were drawn simultaneously from 51 hypothermia treated cardiac arrest patients. One sample (original sample) was analysed when collected, using the Diasorin-method (LIAISON®NSE, LNSE). The other sample was frozen, stored at -70°C (stored sample), and reanalysed in the same laboratory 4-7 years later using both the Diasorin method and a Roche-method (NSE Cobas e601, CNSE). In addition, a comparison of the two methods was performed on 29 fresh samples.

Results: The paired NSE results in original and stored samples were not significantly different, using the LNSE-method. The two methods produced significantly different results (p < 0.0001) on the paired, stored samples, with the CNSE method yielding higher values than the LNSE-method in 96% of samples. The CNSE method resulted in 36% higher values on average. In the method comparison on fresh samples, the CNSE-method generated on average 15% higher values compared to the LNSE-method, and the difference between the paired results was significant (p < 0.0001).

Conclusion: The CNSE method generated consistently higher NSE-values than the LNSE method and this difference was more pronounced when frozen samples were analysed. Tolerability for prolonged freezing was acceptable.

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NSE measured using LIAISON®NSE on original and stored samples with line of equity.
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Fig2: NSE measured using LIAISON®NSE on original and stored samples with line of equity.

Mentions: The median value for NSE in the original samples according to the LIAISON®NSE method was 13.9 μg/L (IQR 10.9-20.5 μg/L, range 6.5-169.7 μg/L). The median NSE value in the stored samples was 14.3 μg/L (IQR 11.1-23.0 μg/L, range 6.5-172.8 μg/L). The differences between the paired original and stored samples were normally distributed with a mean difference of −1.2 μg/L +/−4.8 μg/L (p = 0.12). Figure 1 shows the Bland–Altman plot of the samples. NSE was higher in 34/51 (67%) stored samples compared to the original ones. The correlation coefficient was r = 0.89 (95% CI 0.80 to 0.93) (p < 0.0001), (Figure 2). The equation of the line was y = 1.01 x +0.9 with a 95% CI for the slope of 0.96-1.06, which can be translated into an increase of 1% (95% CI −4 to +6%) for stored samples over the whole range of examined values.Figure 1


Serum neuron specific enolase - impact of storage and measuring method.

Rundgren M, Cronberg T, Friberg H, Isaksson A - BMC Res Notes (2014)

NSE measured using LIAISON®NSE on original and stored samples with line of equity.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4216829&req=5

Fig2: NSE measured using LIAISON®NSE on original and stored samples with line of equity.
Mentions: The median value for NSE in the original samples according to the LIAISON®NSE method was 13.9 μg/L (IQR 10.9-20.5 μg/L, range 6.5-169.7 μg/L). The median NSE value in the stored samples was 14.3 μg/L (IQR 11.1-23.0 μg/L, range 6.5-172.8 μg/L). The differences between the paired original and stored samples were normally distributed with a mean difference of −1.2 μg/L +/−4.8 μg/L (p = 0.12). Figure 1 shows the Bland–Altman plot of the samples. NSE was higher in 34/51 (67%) stored samples compared to the original ones. The correlation coefficient was r = 0.89 (95% CI 0.80 to 0.93) (p < 0.0001), (Figure 2). The equation of the line was y = 1.01 x +0.9 with a 95% CI for the slope of 0.96-1.06, which can be translated into an increase of 1% (95% CI −4 to +6%) for stored samples over the whole range of examined values.Figure 1

Bottom Line: The paired NSE results in original and stored samples were not significantly different, using the LNSE-method.The CNSE method resulted in 36% higher values on average.In the method comparison on fresh samples, the CNSE-method generated on average 15% higher values compared to the LNSE-method, and the difference between the paired results was significant (p < 0.0001).

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Sciences, Division of Anaesthesia and Intensive Care, Lund University, Lund, Sweden. malin.rundgren@skane.se.

ABSTRACT

Background: Neuron specific enolase (NSE) is a recognized biomarker for assessment of neurological outcome after cardiac arrest, but its reliability has been questioned. Our aim was to investigate what influence storage of samples and choice of measuring methods may have on levels of NSE in peripheral blood.

Methods: Two serum samples were drawn simultaneously from 51 hypothermia treated cardiac arrest patients. One sample (original sample) was analysed when collected, using the Diasorin-method (LIAISON®NSE, LNSE). The other sample was frozen, stored at -70°C (stored sample), and reanalysed in the same laboratory 4-7 years later using both the Diasorin method and a Roche-method (NSE Cobas e601, CNSE). In addition, a comparison of the two methods was performed on 29 fresh samples.

Results: The paired NSE results in original and stored samples were not significantly different, using the LNSE-method. The two methods produced significantly different results (p < 0.0001) on the paired, stored samples, with the CNSE method yielding higher values than the LNSE-method in 96% of samples. The CNSE method resulted in 36% higher values on average. In the method comparison on fresh samples, the CNSE-method generated on average 15% higher values compared to the LNSE-method, and the difference between the paired results was significant (p < 0.0001).

Conclusion: The CNSE method generated consistently higher NSE-values than the LNSE method and this difference was more pronounced when frozen samples were analysed. Tolerability for prolonged freezing was acceptable.

Show MeSH
Related in: MedlinePlus