Routine sample transportation of centrifuged barrier tubes impacts certain chemistry analytes.
Author(s): Wang J, Pyle-Eilola AL
Publication: Clin Biochem, 2022, Vol. , Page
PubMed ID: 36058286 PubMed Review Paper? No
Purpose of Paper
The purpose of this paper was to compare levels of the following analytes in plasma separator tubes (PST) that were stored vertically or horizontally post-transport and post-recentrifugation relative to levels in the same specimens prior to transport: white blood cells (WBCs), red blood cells (RBCs), platelets (PLTs), potassium (K), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), sodium (NA), and alanine aminotransferase (ALT). Potential bias in K, AST, LDH, Na, and ALT levels was compared to the significant change limit (SCL).
Conclusion of Paper
Statistically significant increases in LDH and AST levels and Plt counts were observed after specimens were transported in a vertical or horizontal position, and the biases in LDH and AST relative to baseline exceeded the significant change limit (SCL). Significant increases in RBC and WBC counts were also observed after specimens were transport horizontally. After recentrifugation of the vertically transported specimens, only LDH levels were significantly higher than baseline, and exceeded the SCL. In contrast, following recentrifugation of horizontally transported specimens, significant changes in LDH, K and Na levels were observed and the bias in LDH, K and AST exceeded the SCL. No significant changes in ALT were observed.
Studies
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Study Purpose
The purpose of this study was to compare levels of the following analytes in plasma separator tubes (PST) that were stored vertically or horizontally post-transport and post-recentrifugation relative to levels in the same specimens prior to transport: WBC, RBC, Plt, K, AST, LDH, Na, and ALT. Potential bias in K, AST, LDH, Na, and ALT was compared to the significant change limit (SCL). Blood was collected from four healthy volunteers into PST. In addition, twelve leftover blood specimens in PST that were stored for less than 12 h were used for the study. Tubes were centrifuged at 2790 g for 5 min and an aliquot was analyzed. Following initial analysis, eight specimens (6 leftover and 2 volunteer) were placed in a vertical position in a messenger bag, while the eight remaining specimens were placed horizontally in the same bag. An ice pack was placed between the vertical and horizontal specimens and the bag was carried around for 30 min before returning to the lab and analysis. Specimens were then recentrifuged (2790 g for 5 min) and analyzed again. WBC, RBC and platelets were enumerated using a Sysmex XN-1000 analyzer. Levels of LDH, K, AST, sodium (Na), and alanine transaminase (ALT) were quantified by an Ortho Vitros 4600 analyzer. Significant change limit (SCL) was defined as 2.8 times the 30-day coefficient of variance (CV) of the quality control and was 4.20 for LDH, 2.20 for K, 2.50 for AST and 2.20 for Na.
Summary of Findings:
Relative to pre-transport controls, statistically significant (P<0.05) changes in LDH were observed following specimen transport in either position, regardless of recentrifugation, in K only after recentrifugation of specimens transported horizontally, in AST following transport in either position only when not recentrifuged, and in Na only after recentrifugation when transported horizontally. Levels of ALT were not significantly affected by transport regardless of tube position and/or recentrifugation.
Bias in LDH and AST levels were 10.53% and 18.67% when transported vertically, respectively, and 7.14% and 65.02%, when transported horizontally, respectively. Importantly these differences exceeded the SCL of LDH of 4.20 in 75% of specimens transported vertically and 87.5% of specimens transported horizontally and exceeded the AST SCL of 4.50 in 75% of specimens transported vertically and 100% of specimens transported horizontally. The bias in Na and ALT levels following transport were below the SCL, regardless of tube position. In tubes transported vertically, only the mean bias in LDH relative to the initial levels (11.61%) exceeded the SCL after recentrifugation. The bias in LDH following recentrifugation of tubes transported vertically exceeded the SCL in 75% of specimens. In contrast, recentrifugation of tubes transported horizontally generated mean biases in LDH (28.83%), K (2.24%) and AST (5.69%) (relative to pre-transport levels) that exceeded the SCL. The bias in LDH, K and AST following recentrifugation of horizontally transported specimens exceeded the SCL in 87.5%, 50% and 75% of specimens, respectively. Relative to the same specimen after transport, the bias after recentrifugation exceeded the SCL only for AST (-59.33% for horizontal and -16.17% for vertical transport).
Plasma Plt counts increased significantly from baseline (pre-transport) after transport in either position (tubes positioned horizontally or vertically; P<0.05, both), but after recentrifugation counts were comparable to baseline. While WBC and RBC counts were higher following transport than at baseline, the difference was only significant when specimens were transported horizontally (P<0.05) and after recentrifugation no difference from baseline was observed.
Biospecimens
Preservative Types
- None (Fresh)
Diagnoses:
- Not specified
- Normal
Platform:
Analyte Technology Platform Protein Clinical chemistry/auto analyzer Cell count/volume Hematology/ auto analyzer Electrolyte/Metal Clinical chemistry/auto analyzer Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Storage Within hospital transportation method Hand-delivered
Not transported
Biospecimen Aliquots and Components Centrifugation Different number of centrifugation steps compared
Storage Specimen transport duration/condition Horizontal tube
Vertical tube