Hemolysis associated with pneumatic tube system transport for blood samples.
Objective The frequency of hemolysis of blood samples may be increased by transport in a pneumatic tube system. The purpose of this study was to evaluate the effect of pneumatic tube system transport on hemolysis of blood samples.Methods: Blood samples were transported from the emergency department to the hospital laboratory manually by hospital staff (49 patients) or with a pneumatic tube system (53 patients). The hemolysis index and serum chemistry studies were performed on the blood samples and compared between the different methods of transport.Results: The blood samples that were transported by the pneumatic tube system had a greater frequency of hemolysis and greater mean serum potassium and median creatinine aspartate aminotransferase and lactate dehydrogenase levels than samples transported manually.Conclusion: Blood samples transported from the emergency department to the hospital laboratory by a pneumatic tube system may have a greater frequency of hemolysis than samples transported manually. This may necessitate repeat phlebotomy and cause a delay in completing the laboratory analysis.
KEY WORDS: Analysis Blood Biochemistry Hematology.
Hospital care requires transport of numerous drugs clinical specimens medical instruments radiographs and laboratory reports between departments. This is costly to hospitals and requires the employment of hospital transportation staff. Pneumatic tube systems are available to transport clinical specimens drugs radiographs and laboratory reports more rapidly and safely than manual transport by hospital workers.1 However the transport method may affect the quality of samples.2 Rapid transport of blood samples in pneumatic tube systems may cause red blood cell breakdown (hemolysis) and may affect blood test results.34 Hemolysis of blood samples may necessitate repeated phlebotomy and may cause inaccuracy and delays in completing laboratory tests that are needed for clinical decision-making.5
Recently the pneumatic tube system in our hospital was out of order. Blood samples from patients in the emergency department were transported manually by hospital staff from the emergency department to the laboratory. During this time we observed that laboratory results frequently were normal including the hemolysis index. When the pneumatic tube system was repaired and functional for transport of blood samples the hemolysis index was higher. Therefore we performed this study to evaluate the effect of the pneumatic tube system on hemolysis of blood samples. We hypothesized that the pneumatic tube system may cause hemolysis of blood samples that may necessitate repeat phlebotomy and cause delays in patient care.
Study Design: This study was performed after the approval of the Ethic Board of Konya Numune Hospital. From 09.12.2011 to 15.12.2011 the hospital pneumatic tube system was not functioning and blood samples were transported manually by hospital staff from the emergency department to the laboratory for evaluation of biochemical parameters; manually-transported blood samples were randomly selected from 49 patients for the study. From 16.12.2011 to 22.12.2011 the hospital pneumatic tube system was functional and used for transport of blood samples from the emergency department to the laboratory; blood samples that were transported by the pneumatic tube system were randomly selected from 53 patients for the study. In this study all blood samples were taken from a single vein with an injection by a phlebotomist. The blood samples were inserted into the tubes containig no anticoagulant heparin K2EDTA or citrate (BD Vacutainer SST II Advance UK). While the samples taken in the first week were transferred from the emergency department to the central laboratory with the help of a porter the samples obtained in the second week were trasferred through the pneumatic tube system. The blood samples of both groups were centrifuged at3500 rpm for 10 min. Hemolysis index of the samples was determined with spectrophotometry. Other quantitative clinical biochemical studies included serum sodium potassium calcium glucose urea nitrogen creatinine alanine aminotransferase aspartate aminotransferase lactate dehydrogenase total bilirubin and amylase.Pneumatic tube system: Pneumatic tube system (Swisslog Compact Station Germany) used in the hospital is running at 3m/sec. Our pneumatic tube system contains carriers with sponge to prevent the tubes to hit each other and enables them to move. These carriers are made of polycarbonate in 86 mm diameter and 220 mm long The distance of the pneumatic tube system between emergency department and central laboratory was approximately 80 meters. Since the emergency department and the central laboratory are on the ground floor of the hospital the shortest distance of the pneumatic tube system was between emergency department and the central laboratory.Statistical analysis: Data analysis was performed with statistical software (Genstat 7 Release 7 VSN International Hemel Hempstead UK).6Distribution properties of laboratory tests were evaluated with Anderson-Darling normality test. Normally distributed data were compared with t test. Data that were not normally distributed were compared with Mann-Whitney test. Hemolysis index of specimens transported with the pneumatic tube system and manual transport were compared with odds ratios. Statistical significance was defined by P = .05.
The blood samples that were transported by the pneumatic tube system had a greater frequency of hemolysis and greater mean serum potassium and median creatinine aspartate aminotransferase and lactate dehydrogenase than samples transported manually (Table-I). The samples that were transported by the pneumatic tube system had hemolysis 532-fold more hemolysis (95% confidence interval: 30 to 9486) than samples that were transported manually. There were no other differences in serum blood parameters between samples transported by the pneumatic tube system or manually (Table-I).
The present results showed that samples transported by the pneumatic tube system had a markedly greater frequency of hemolysis than samples transported manually (Table-I). The pneumatic tube system may have caused hemolysis because of the high transportation speed sudden changes in direction of the transport containers and pressure caused by the system on the samples. Therefore it may be prudent to monitor for hemolysis in blood samples transported by pneumatic tube systems. At installation of the pneumatic tube system sudden changes in direction may be avoided. In addition the speed and pressure of the
Table-I: Relation between method of transport of blood specimens and results of laboratory studies
Parameters###Manual (n = 49)###Pneumatic tube system (n = 53)###Pless than
Hemolysis (number [%])###8 (16)###53 (100)###0.0001
Sodium (mmol/L)###141 (140 to 142)###141 (139 to 142)###NS
Potassium (mmol/L)###4.3 0.4###4.6 0.5###0.001
Calcium (mg/dL)###9.4 0.6###9.3 0.6###NS
Glucose (mg/dL)###106 (93 to 123)###112 (95 to 161)###NS
Urea nitrogen (mg/dL)###32 (25 to 39)###35.50 (29.75 to 43.0)###NS
Creatinine (mg/dL)###0.80 (0.70 to 0.90)###0.90 (0.80 to 1.0)###0.001
Alanine aminotranferase (U/L)###18 (14 to 27)###18 (14 to 31)###NS
Aspartate aminotranferase (U/L)###19 (16 to 24)###27 (21 to 36)###0.0001
Lactate dehydrogenase (U/L)###190 (166 to 220)###284.5 (228 to 384)###0.0001
Bilirubin total (mg/dL)###0.60 (0.45 to 0.80)###0.55 (0.40 to 1.03)###NS
Amylase (U/L)###59 (46 to 72)###66 (45 to 86)###NS
optimized to minimize hemolysis of blood samples. It is important that blood tests have sufficient accuracy for correct interpretation of results for clinical decision-making. Therefore hospitals must address factors that may affect the accuracy of laboratory results. Hemolysis may be prevented by using gel in test tubes for blood collection.7Furthermore conveyor containers can be lined with cotton and protective circular rings to prevent hemolysis by minimizing acceleration and deceleration of samples during transport.Hemolysis may be caused by in vivo factors such as hemolytic anemia or blood transfusions or in vitro factors such as osmotic physical mechanical or chemical factors. In the present study the pneumatic tube system was associated with hemolysis of transported blood samples (Table-I). Abnormalities of potassium magnesium phosphate aspartate aminotranferase and lactate dehydrogenase have been observed previously in blood samples transported by pneumatic tube systems.7-11 The length of the pneumatic tube system and transfer speed may increase the pressure on erythrocytes and cause hemolysis.12 Hemolysis also may be caused by high speed rapid acceleration or rapid deceleration during sample transport in a pneumatic tube system.In a previous study the frequency of hemolysis differed between manual transport (16.2%) and a pneumatic tube system (13.7%).3 In another study the frequency of hemolysis was greater with a pneumatic tube system (10.9%) than manual transport (3.3%) and failure of the pneumatic tube system caused in increase in the frequency of hemolysis (55%).4 The frequency of hemolysis observed in the present study (Table-I) was marked higher than previously reported. This difference between studies may have been caused by different characteristics of the pneumatic tube systems. Previous studies also showed changes in potassium lactate dehydrogenase iron magnesium and uric acid levels because of hemolysis from sample transport in a pneumatic tube system.13 The hemolysis index may be helpful to control the unity of samples and is a simple and inexpensive marker to quantify the quality of samples before analysis.14Evliyaoglu et al. reported that the hemolysis rate of plasma samples increased very slowly as the pneumatic tube system transport rate and distance increased.15 In our study although the distance between the emergency department and the central laboratory was the shortest the hemolysis index was very high.
The present study showed that blood samples transported by a pneumatic tube system may develop hemolysis during transport. Prudent quality control measures may include monitoring the hemolysis index of samples transported by the pneumatic tube system and evaluating the physical parameters of the system that may contribute to hemolysis.
Funding acknowledgement: This research received no specific grant from any funding agency in the public commercial or not-for-profit sectors.
Declaration of conflicting interests: The authorsdeclare that there is no conflict of interest.
1. Keshgegian AA Bull GE. Evaluation of a soft-handling computerized pneumatic tube specimen delivery system. Effects on analytical results and turnaround time. Am J Clin Pathol. 1992;97:535-540.2. Collinson PO John CM Gaze DC Ferrigan LF Cramp DG.Changes in blood gas samples produced by a pneumatictube system. J Clin Pathol. 2002;55:105-107.3. Stair TO Howell JM Fitzgerald DJ Bailey SC BastaschMD. Hemolysis of blood specimens transported fromED to laboratory by pneumatic tube. Am J Emerg Med.1995;13:484.4. Ellis G. An episode of increased hemolysis due to adefective pneumatic air tube delivery system. Clin Biochem.2009;42(12):1265-1269.5. Fernandes CM Worster A Eva K Hill S McCallum C.Pneumatic tube delivery system for blood samples reducesturnaround times without affecting sample quality. J EmergNurs. 2006;32:139-143.6. Payne RW Murray DA Harding SA Baird DB SoutarDM. GenStat for Windows 7th ed. Introduction. VSNInternational Hemel Hempstead 2003.7. Sodi R Darn SM Stott A. Pneumatic tube system inducedhaemolysis: assessing sample type susceptibility tohaemolysis. Ann Clin Biochem. 2004;41:237-240.8. Guder WG da Fonseca-Wollheim F Heil W Schmitt YMTAlpfer G Wisser H et al. The haemolytic icteric and lipemicsample. Recommendations regarding their recognition andprevention of clinically relevant interferences. J Lab Med.2000;24:357-364. 9. Kratz A Salem RO Van Cott EM. Effects of a pneumatic tube system on routine and novel hematology and coagulation parameters in healthy volunteers. Arch Pathol Lab Med.2007;131:293-296.10. Poznanski W Smith F Bodley F. Implementation of apneumatic-tube system for transport of blood specimens.Am J Clin Pathol. 1978;70:291-29511. Zanner R Moser N Blobner M Luppa PB. Transport ofblood gas samples: is the pneumatic tube system safeAnaesthesist. 2006;55:1099-1104.12. Throckmorton AL Kapadia JY Chopski SG Bhavsar SSMoskowitz WB Gullquist SD et al. Numerical hydraulicand hemolytic evaluation of an intravascular axial flowblood pump to mechanically support Fontan patients. AnnBiomed Eng. 2011;39:324-336.13. Weaver DK Miller D Leventhal EA Tropeano V.Evaluation of a computer-directed pneumatic-tube systemfor pneumatic transport of blood specimens. Am J ClinPathol. 1978;70:400-405.14. Plebani M Lippi G. Hemolysis index: quality indicatoror criterion for sample rejection Clin Chem Lab Med.2009;47:899-902.15. Evliyaoglu O Toprak G Tekin A Basarali MK Kilinc CColpan L. Effect of Pneumatic Tube Delivery System Rateand Distance on Hemolysis of Blood Specimens. J Clin LabAnal. 2012;26:66-69.
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|Publication:||Pakistan Journal of Medical Sciences|
|Date:||Feb 28, 2014|
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