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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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Related in: MedlinePlus

Bland-Altman plot showing the difference between the stored samples analysed using the LIAISON and the NSE Cobas e601 respectively. The samples were exposed to identical preanalytical conditions. The difference between the NSE levels analysed on the LIAISON®NSE and the NSE Cobas e601 are shown on the y-axis and the mean between the LIAISON®NSE and the NSE Cobas e601 NSE levels on the x-axis. The solid line denotes the mean difference between the analyses and the hatched line the upper and lower 1.96 SD lines.
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Fig3: Bland-Altman plot showing the difference between the stored samples analysed using the LIAISON and the NSE Cobas e601 respectively. The samples were exposed to identical preanalytical conditions. The difference between the NSE levels analysed on the LIAISON®NSE and the NSE Cobas e601 are shown on the y-axis and the mean between the LIAISON®NSE and the NSE Cobas e601 NSE levels on the x-axis. The solid line denotes the mean difference between the analyses and the hatched line the upper and lower 1.96 SD lines.

Mentions: The median NSE-level in stored samples according to the NSE Cobas e601 method was 16.3 μg/L (IQR 11.8-28.5 μg/L, range 0.5-231.2 μg/L). The mean difference between LIAISON®NSE and the NSE Cobas e601 methods on the stored samples was −5.4 μg/L, (SD 9.5 μg/L), with 95% limits of agreement +/−19.4 μg/L (Figure 3).The differences between the paired NSE results were not normally distributed. The difference between the paired data was significant (p < 0.0001). The NSE Cobas e601 method showed consistently higher NSE values than the LIAISON®NSE method, with a higher value in 49/51 (96%) of samples. The correlation coefficient was r = 0.97 (CI 0.95-0.98, p < 0.0001). Figure 4 shows the scatter of samples and the assessed linearity. The equation of the line was y = 1.36 × −3.4 with a 95% CI for the slope of 1.33 to 1.38, which can be translated into a 36% (95% CI 33–38%) increase in NSE level using the NSE Cobas e601 method.Figure 3


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

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

Bland-Altman plot showing the difference between the stored samples analysed using the LIAISON and the NSE Cobas e601 respectively. The samples were exposed to identical preanalytical conditions. The difference between the NSE levels analysed on the LIAISON®NSE and the NSE Cobas e601 are shown on the y-axis and the mean between the LIAISON®NSE and the NSE Cobas e601 NSE levels on the x-axis. The solid line denotes the mean difference between the analyses and the hatched line the upper and lower 1.96 SD lines.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig3: Bland-Altman plot showing the difference between the stored samples analysed using the LIAISON and the NSE Cobas e601 respectively. The samples were exposed to identical preanalytical conditions. The difference between the NSE levels analysed on the LIAISON®NSE and the NSE Cobas e601 are shown on the y-axis and the mean between the LIAISON®NSE and the NSE Cobas e601 NSE levels on the x-axis. The solid line denotes the mean difference between the analyses and the hatched line the upper and lower 1.96 SD lines.
Mentions: The median NSE-level in stored samples according to the NSE Cobas e601 method was 16.3 μg/L (IQR 11.8-28.5 μg/L, range 0.5-231.2 μg/L). The mean difference between LIAISON®NSE and the NSE Cobas e601 methods on the stored samples was −5.4 μg/L, (SD 9.5 μg/L), with 95% limits of agreement +/−19.4 μg/L (Figure 3).The differences between the paired NSE results were not normally distributed. The difference between the paired data was significant (p < 0.0001). The NSE Cobas e601 method showed consistently higher NSE values than the LIAISON®NSE method, with a higher value in 49/51 (96%) of samples. The correlation coefficient was r = 0.97 (CI 0.95-0.98, p < 0.0001). Figure 4 shows the scatter of samples and the assessed linearity. The equation of the line was y = 1.36 × −3.4 with a 95% CI for the slope of 1.33 to 1.38, which can be translated into a 36% (95% CI 33–38%) increase in NSE level using the NSE Cobas e601 method.Figure 3

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