Short-term stability of free metanephrines in plasma and whole blood

2020 ◽  
Vol 58 (5) ◽  
pp. 753-757 ◽  
Author(s):  
Elisa Danese ◽  
Martina Montagnana ◽  
Claudio Brentegani ◽  
Giuseppe Lippi
Keyword(s):  
Whole Blood ◽  
Repeated Measures ◽  
Sample Collection ◽  
Short Term ◽  
Total Change ◽  
Term Stability ◽  
Before And After ◽  
Liquid Chromatography Tandem Mass ◽  
The Mean ◽  
The Stability

AbstractBackgroundAnalysis of plasma metanephrine (MN) and normetanephrine (NMN) with liquid chromatography tandem mass spectrometry (LC-MS/MS) is the gold standard for the screening of pheochromocytomas and paragangliomas (PPGLs). As scarce information is available on the stability of MNs in diagnostic samples, this study was aimed at analyzing the short-term stability of plasma free MNs in whole blood and plasma, using LC-MS/MS.MethodsThe stability of plasma MNs was evaluated after sample collection at 1, 2 and 3 h in whole blood, and at 2, 4 and 6 h in centrifuged samples. Both studies were performed while maintaining the samples at room temperature (RT) and at 4 °C. The ClinMass Complete Kit (Recipe, Munchen, Germany) was used for measuring MNs with LC-MS/MS (Nexera X2 UHPLC-4500MD Sciex). Differences from the baseline (T0) were assessed using repeated measures one-way ANOVA, Students’ paired t-test and a comparison of the mean percentage changes with the total change limit (TCL).ResultsStatistically significant differences from T0 were found for both MNs (p < 0.001) in whole blood stored at RT, and for NMN (p = 0.028) but not MN (p = 0.220) at 4 °C. The mean difference exceeded the TCL after 1 h and 3 h at RT for MN, and after 1 h at RT for NMN. Statistically significant differences from T0 were only observed in the plasma samples for NMN at RT (p = 0.012), but the variation was within the TCL.ConclusionsMN and NMN displayed different patterns of stability before and after centrifugation. Even short-time storage at RT in whole blood should hence be avoided.

scholarly journals Quantification of Cefepime, Meropenem, Piperacillin, and Tazobactam in Human Plasma Using a Sensitive and Robust Liquid Chromatography-Tandem Mass Spectrometry Method, Part 2: Stability Evaluation

2018 ◽  
Vol 62 (9) ◽  
Author(s):  
Ronilda D'Cunha ◽  
Thanh Bach ◽  
Beth Ann Young ◽  
Peizhi Li ◽  
Demet Nalbant ◽  
...  
Keyword(s):  
Human Plasma ◽  
Whole Blood ◽  
Room Temperature ◽  
Solution Stability ◽  
Short Term ◽  
Term Stability ◽  
Degradation Rates ◽  
Liquid Chromatography Tandem Mass ◽  
The Stability ◽  
Stability Results

ABSTRACT Although the stability of β-lactam antibiotics is a known issue, none of the previously reported bioanalytical methods had an adequate evaluation of the stability of these drugs. In the current study, the stability of cefepime, meropenem, piperacillin, and tazobactam under various conditions was comprehensively evaluated. The evaluated parameters included stock solution stability, short-term stability, long-term stability, freeze-thaw stability, processed sample stability, and whole-blood stability. When stored at −20°C, the stock solution of meropenem in methanol was stable for up to 3 weeks, and the stock solutions of cefepime, piperacillin, and tazobactam were stable for up to 6 weeks. All four antibiotics were stable in human plasma for up to 3 months when stored at −80°C and were stable in whole blood for up to 4 h at room temperature. Short-term stability results indicated that all four β-lactams were stable at room temperature for 2 h, but substantial degradation was observed when the plasma samples were stored at room temperature for 24 h, with the degradation rates for cefepime, meropenem, piperacillin, and tazobactam being 30.1%, 75.6%, 49.0%, and 37.7%, respectively. Because the stability information is method independent, our stability results can be used as a reference by other research groups that work with these antibiotics.

Analytical Features of the New Red Blood Cell and White Blood Cell LH750 Research Population Data.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3841-3841
Author(s):  
Josep Piqueras ◽  
Maria J. Capel ◽  
Jose J. Duran ◽  
Pedro J. Jimenez
Keyword(s):  
Blood Cell ◽  
Population Data ◽  
Short Term ◽  
Term Stability ◽  
Normal Individuals ◽  
Blood Drawing ◽  
Research Population ◽  
The Mean ◽  
The Stability

Abstract Recently, a new set of parameters produced by the Beckman-Coulter’s GEN’S, LH500, LH750 and the latest LH780 automated blood counters, derived from leukocyte and red cell’s morphological data by means of the VCS technology are available and can be printed as research data together with the leukocyte differential and reticulocyte analysis. With the use of these Research Population Data (RPD) parameters several recent publications have shown their usefulness for the diagnosis of malaria (Fourcade et al), sepsis (Chaves ), apoptosis detection (Lab hem 2005) and the diagnosis and differentiation of lymphoptoliferative disorders (Silva M et al) In order to evaluate the analytical behaviour of these newly described red blood cell and leukocyte morphological parameters in routine bood samples and in the Beckman-Coulter’s calibration and control 5C, we conducted a study to evaluate the paramters’ precision and performance during short and long term sample’s storage: Precision: 10 samples from normal individuals were analyzed 10 times and the CV for each parameter was calculated Short term stability stability at 4C and 22C: 5 normal samples were evaluated from the time of blood drawing until 5 hours later, both at room temperature (22C) and at 4 C Long term stability at 4C: 15 normal samples were evaluated at various times after blood drawing, from 4 hours (which was found to be the best time for sample analysis in the short term stability study, above) up to 77 hours after blood withdrawal. Control and Calibration with 5C: We evaluated the performance of the research parameters in the 5C by running the same batch of 5C control in 5 different counters from 4 different centers, comparing the results with those from 5 normal individuals Stability in a period of time: We have evaluated every week during two months 15 normal samples, recording the temperature and the avergae of all RPD values. RESULTS Precission: The CV% for the Mean Volume, Conductivity and Scatter of the different leukocyte types was always less than 1%, with an average of 0,6%. The CV% for the Standard Deviation of Volume, Conductivity and Scatter varied between 2.45% and 7.7%, wit an average of 4.9%. The CV% of any SD always being higher than the primary parameter. Short term stability: We observed no significant differences between samples kept at 4C and 22C during the first 5 hours after blood drawing. During the first two hours, however, minor fluctuations in results occurred, always <5%, being preferable to test the samples after blood stabilization, between 2 and 5 hours after withdrawal. Long term stability: The stability of the research parameters after 9 hours is best when the samples are kept at 4C, but the differences are not clinically significant up to 17 hours and, for some parameters, up to 24 hours after blood drawing. The comparison of the RPD research parameters from normal samples and from the Beckman’s 5C control showed good correlation in the different counters and the different centers. When the results from the 5C were higher or lower, the results from the normal samples were concordantly higher or lower respectively, The correlation coefficient was 0.98 for the Mean Volume and 0.92 for the Mean Conductivity The Stability of RPD values was acceptable during the period evaluated (2 m.)with changes lower than 3%. CONCLUSIONS: The results of the present study show that from the analytical stand point, precission, stability and possibility of calibration, these Research Population data are equivalent to those of other laboratory tests performed by modern instruments.

scholarly journals A SLR Pre-Processing Algorithm Based on Satellite Signature Effect

2021 ◽  
Vol 11 (19) ◽  
pp. 8880
Author(s):  
Bowen Guan ◽  
Cunbo Fan ◽  
Ning An ◽  
Ricardo Cesar Podesta ◽  
Dra Ana Pacheco ◽  
...  
Keyword(s):  
Mean Value ◽  
Observation Data ◽  
Short Term ◽  
Error Sources ◽  
Effect Model ◽  
The Mean ◽  
The Stability ◽  
First Time ◽  
Satellite Signature Effect

As one of the major error sources, satellite signature effect should be reduced or even erased from the distribution of the post-fit residuals to improve the ranging precision. A simulation of satellite signature effect removal process for normal point algorithm is conducted based on a revised model of satellite response, which fully considers the structural and distribution characteristics of retroreflectors. In order to eliminate both long-term and short-term satellite signature effect, a clipping method for SLR data processing is proposed by defining the clipping location as 5.6 mm away from the mean value of the long-term fit residuals to select effective returns for normal points. The results indicate that, compared to normal points algorithm, the RMS per NP of LAGEOS-1 observation data processed by the clipping method is reduced from 62.90 ± 9.9 mm to 56.07 ± 4.69 mm, and the stability of RMS is improved 53%. This study improves the satellite signature effect model and simulates the fluctuation of normal points caused by satellite signature effect for the first time. The new method based on the simulation of satellite signature effect has stronger robustness and applicability, which can further minimize the influence of satellite signature effect on the SLR production and significantly improve the data property.

Fabrication of Boron Compensated Hydrogenated Amorphous Silicon Films with Significantly Improved Stability Using Plasma Enhanced Chemical Vapor Deposition Technique

1995 ◽  
Vol 377 ◽  
Author(s):  
Mohan K. Bhan
Keyword(s):  
Chemical Vapor ◽  
Short Term ◽  
Term Stability ◽  
Long Term Stability ◽  
Vapor Deposition Technique ◽  
Improved Stability ◽  
Donor Acceptor ◽  
B Doping ◽  
The Stability

ABSTRACTWe have systematically investigated the effects of addition of sub-ppm levels of boron on the stability of a-Si:H films and p-i-n devices, deposited by PE-CVD technique. The films thus produced with appropriate amounts of boron, show a significant improvement in stability, when soaked under both AM 1.5 (short-term) as well as 10×sun (long-term) illumination conditions. The opto-electronic properties of the films are quite respectable It is concluded that boron compensates the native impurities by forming donor-acceptor pairs, which reduces the “fast” defects and hence the initial degradation of the films. It is also speculated that boron may also be improving the short-term stability, by reducing the recombination of light generated electrons and holes, by converting D° into D+ states. The long-term stability appears to get affected by hydrogen dilution which seems to reduce the amount of “slow” defects. As a result of B doping of i-layer, the initial conversion efficiency of the devices decreases. It is presumed that our devices may contain an enhanced level of boron impurity, than expected, making them as worse material and to degrade less.

scholarly journals Studies on the Stability of Acrylamide in Food During Storage

2005 ◽  
Vol 88 (1) ◽  
pp. 268-273 ◽  
Author(s):  
Katrin Hoenicke ◽  
Robert Gatermann
Keyword(s):  
Milk Powder ◽  
Internal Standard ◽  
Food Samples ◽  
Reaction Products ◽  
Before And After ◽  
Raw Sugar ◽  
Liquid Chromatography Tandem Mass ◽  
Sh Group ◽  
The Stability ◽  
Soluble Coffee

Abstract Acrylamide levels in a variety of food samples were analyzed before and after 3 months of storage at 10°–12°C. The analysis was performed by liquid chromatography tandem mass spectrometry (LC/MS/MS) using deuterium-labeled acrylamide as internal standard. Acrylamide was stable in most matrixes (cookies, cornflakes, crispbread, raw sugar, potato crisps, peanuts) over time. However, slight decreases were determined for dietary biscuits (83–89%) and for licorice confection (82%). For coffee and cacao powder, a significant decrease occurred during storage for 3 or 6 months, respectively. Acrylamide concentrations dropped from 305 to 210 μg/kg in coffee and from 265 to 180 μg/kg in cacao powder. On the contrary, acrylamide remained stable in soluble coffee as well as in coffee substitutes. Reactions of acrylamide with SH group-containing substances were assumed as the cause for acrylamide degradation in coffee and cacao. Spiking experiments with acrylamide revealed that acrylamide concentrations remained stable in baby food, cola, and beer; however, recovery levels dropped in milk powder (71%), sulfurized apricot (53%), and cacao powder (17%). These observations suggest that variations in the acrylamide content of food, especially in coffee and cacao, can vary depending on the storage time because special food constituents and/or reaction products can affect the levels.

Short-Term Stability of Whole Blood Polyunsaturated Fatty Acid Content on Filter Paper During Storage at −28 °C

Lipids ◽  
2016 ◽  
Vol 51 (2) ◽  
pp. 193-198 ◽  
Author(s):  
Daniele Pupillo ◽  
Manuela Simonato ◽  
Paola E. Cogo ◽  
Alexandre Lapillonne ◽  
Virgilio P. Carnielli
Keyword(s):  
Fatty Acid ◽  
Polyunsaturated Fatty Acid ◽  
Filter Paper ◽  
Whole Blood ◽  
Acid Content ◽  
Fatty Acid Content ◽  
Short Term ◽  
Term Stability ◽  
Polyunsaturated Fatty Acid Content

Long- and short-term in vitro D-dimer stability measured with INNOVANCE D-Dimer

2010 ◽  
Vol 103 (02) ◽  
pp. 461-465 ◽  
Author(s):  
Martina Böhm-Weigert ◽  
Thomas Wissel ◽  
Heidrun Muth ◽  
Bettina Kemkes-Matthes ◽  
Dirk Peetz
Keyword(s):  
Frozen Storage ◽  
Percentage Change ◽  
Short Term ◽  
Term Stability ◽  
Long Term Stability ◽  
Repeated Freezing ◽  
The Mean ◽  
D Dimer

Summary In vitro D-dimer stability in plasma is widely assumed, but has not yet been documented by systematic studies using samples covering a wide range of D-dimer. We investigated the short- and long-term stability of D-dimer in clinical citrated plasma samples with normal and pathological levels. The short-term stability was analysed by measuring D-dimer fresh, after storage of plasma for 4 hours at room temperature (RT) and after an additional 24 h storage at +2 to +8°C (n=40). Long-term stability samples (n=40) were measured fresh and after storage for 19, 25 and 36 months at ≤-60°C. The effect of repeated freezing was analysed by measuring samples (n=50) fresh and after four consecutive freeze-thaw cycles. D-dimer was measured on the BCS System using the INNOVANCE D-Dimer assay (Siemens Healthcare Diagnostics Products GmbH, Marburg, Germany). D-dimer values at baseline ranged from 0.23–22.2 mg/l FEU. The mean percentage change after storage for 4 hours at RT and additional 24 hours at +2 to +8°C was +3.8% and +2.7%, respectively. The mean percentage change after frozen storage for 19, 25 and 36 months at ≤-60°C was –11.7%, –4.8% and –9.3%, respectively. The small decrease of D-dimer values after frozen storage was not time-dependent. Repeated freezing did not significantly alter D-dimer values (mean change ≤5%). The data demonstrate stability of D-dimer in plasma prior to freezing for up to 4 hours at RT and for up to 24 hours at +2 to +8°C as well as in plasma stored for up to three years at ≤-60°C.

scholarly journals Choline in Whole Blood and Plasma: Sample Preparation and Stability

2008 ◽  
Vol 54 (3) ◽  
pp. 590-593 ◽  
Author(s):  
Bingfang Yue ◽  
Elizabeth Pattison ◽  
William L Roberts ◽  
Alan L Rockwood ◽  
Oliver Danne ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Whole Blood ◽  
Storage Time ◽  
Storage Temperature ◽  
Sample Collection ◽  
Coronary Syndrome ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Heparin Plasma ◽  
Liquid Chromatography Tandem Mass

Abstract Background: Choline is critical for a variety of biological functions and has been investigated as a biomarker for various pathological conditions including acute coronary syndrome. Methods: A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was used to quantify choline in whole blood and plasma in freshly collected samples prepared with ultrafiltration or protein precipitation. We investigated the effects of preanalytical variables including types of anticoagulants and storage temperature and time. Results: We observed no significant differences in whole-blood choline concentration in EDTA-anticoagulated vs heparin-anticoagulated samples: mean (SD) difference 0.9% (3.2%), P = 0.80. For plasma, choline concentrations with heparin in 5 of 12 volunteers were &gt;10% higher than with EDTA, P = 0.01. One freeze-thaw cycle led to significant mean (SD) increases in choline concentrations in heparin whole blood, 19.3% (11.4%), P &lt;0.01, and the effect was not significant for other sample types studied (P &gt;0.33). For freshly collected samples stored at ambient temperature, choline concentrations in all types of samples increased with storage time. For EDTA whole blood, EDTA plasma, and heparin plasma, the choline concentration increased for the first 60 min and then stabilized. For heparin whole blood, the choline concentration continued to increase linearly with storage time for &gt;4 h, at which time the choline concentrations were increased by approximately 50%. Conclusions: Sample collection, storage, and sample preparation procedures are critical for clinical measurements of choline in whole blood and plasma.

scholarly journals Short-Term Stability of Hematologic Parameters in Frozen Whole Blood

2019 ◽  
Vol 4 (3) ◽  
pp. 410-414
Author(s):  
Olive Tang ◽  
Elizabeth Selvin ◽  
Valerie Arends ◽  
Amy Saenger
Keyword(s):  
Whole Blood ◽  
Short Term ◽  
Term Stability

Evaluation of the Stability of the Subjects with Anterior Cruciate Injuries Reconstruction

2020 ◽  
Author(s):  
Hossein Akbari Aghdam ◽  
Mahsa Kavyani ◽  
Maryam Bosak ◽  
Mohammad Taghi Karimi ◽  
Mehdi Motififard
Keyword(s):  
Acl Reconstruction ◽  
Postural Stability ◽  
Center Of Pressure ◽  
Mean Value ◽  
P Value ◽  
Before And After ◽  
The Mean ◽  
The Difference ◽  
Anterior Cruciate ◽  
The Stability

AbstractAnterior cruciate ligament (ACL) is the most frequently injured ligament in the knee and is often injured during sport-related activities. ACL injuries influence the abilities of the subjects during standing and walking. Although early surgical intervention is preferred treatment for the majority of knee surgeons, the effect of this approach on postural stability of patients is not fully understood. Therefore, the aim of this study was to determine the difference between stability of ACL-reconstructed subjects before and after surgery. A group of 15 consecutive ACL injured patients participated in this study. Postural stability of the patients was evaluated 1 week before and 6 months after surgery (ACL reconstruction with hamstring autograft). A Kistler force plate was used to evaluate center of pressure (COP) sway during quiet standing. The mean values of the COP parameters were obtained in pre and postsurgery conditions. Paired sample t-test was used to evaluate the difference between the stability parameters of the two conditions. The significant point was set at 0.05. The mean value of path length of COP velocity in mediolateral (ML) direction was 1,485.57 ± 479.42 mm and 2,641.33 ± 996.26 mm before and after surgery, respectively (p-value = 0.01). Although the mean value of COP velocity in anteroposterior and ML directions increased after surgery, the difference was only significant for velocity in ML direction (p-value = 0.049). The results of this study showed that the standing stability of those with ACL reconstruction decreased significantly after ACL reconstruction, which may be due to the effects of the surgery on sensory mechanism of ACL and inability of patients to return to their previous deep sense perception and knee proprioception.

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