Measurement of serum and plasma osmolality in healthy young humans – influence of time and storage conditions

Author(s):  
Christian C. Seifarth ◽  
Johannes Miertschischk ◽  
Eckhardt G. Hahn ◽  
Johannes Hensen

AbstractBackground: The precise measurement of osmolality is crucial in the differential diagnosis of disorders of water balance. Storage conditions, and freezing and thawing of serum or plasma samples before osmometry may influence the accuracy of measured values. Methods: A series of serum and plasma samples of 25 healthy young individuals were stored under different conditions at different temperatures (room temperature (22°C), 7°C, –21°C, –78°C) for up to 56 days. Before freezing a protein-stabilizing agent (bacitracin) was added to one part of the samples. Osmolality was examined using the freezing point method. Results: At room temperature osmolality was stable for up to 3 days but showed a tendency toward an increase that was significant on day 14. In contrast, at 7°C an initial significant decrease in serum osmolality occurred (day 1), which was followed by a slow increase. Serum samples stored at –21°C showed a significantly lower osmolality on the 14th day compared to baseline. Adding bacitracin before freezing reduced this decrease by more than half, but the deviation was still significant. In samples stored at –78°C no significant alteration of osmolality from baseline was observed over the observation period of 56 days if samples were thawed in a 37°C water bath. Conclusion: Immediate measurement of osmolality is most reliable in order to obtain accurate values, although storing at room temperature does not influence osmolality significantly during the first 3 days. If storage is necessary for longer, samples should be stored at –78°C and must be thawed quickly (at 37°C). Under these conditions reliable values can be obtained from frozen serum or plasma. Storage at 7°C is not recommended. If samples are stored at –21°C the addition of a protein-stabilizing agent may be useful.

1992 ◽  
Vol 38 (11) ◽  
pp. 2278-2280 ◽  
Author(s):  
N Bohnen ◽  
D Terwel ◽  
M Markerink ◽  
J A Ten Haaf ◽  
J Jolles

Abstract The reliability of measurements of plasma osmolality is known to be biased by technical artifacts, such as the anticoagulant and the osmometric technique used; the resulting measurement errors therefore may cause errors in interpretation of data. In assessing the potential biasing influence of procedural variables, we found that the temperature at which fresh plasma samples were stored, the duration of storage, and the freezing and thawing of samples appeared to significantly (P < 0.01) affect osmolality values around the narrow physiological range. These factors should be considered in the interpretation of studies on the osmoregulation of vasopressin secretion. In particular, the results suggest that data obtained for any but fresh samples, whether frozen-thawed samples or samples stored at room temperature, are unreliable.


2018 ◽  
Vol 56 (7) ◽  
pp. 1054-1062 ◽  
Author(s):  
Olga Kofanova ◽  
Estelle Henry ◽  
Rocio Aguilar Quesada ◽  
Alexandre Bulla ◽  
Hector Navarro Linares ◽  
...  

Abstract Background: Longer pre-centrifugation times alter the quality of serum and plasma samples. Markers for such delays in sample processing and hence for the sample quality, have been identified. Methods: Twenty cytokines in serum, EDTA plasma and citrate plasma samples were screened for changes in concentration induced by extended blood pre-centrifugation delays at room temperature. The two cytokines that showed the largest changes were further validated for their “diagnostic performance” in identifying serum or plasma samples with extended pre-centrifugation times. Results: In this study, using R&D Systems ELISA kits, EDTA plasma samples and serum samples with a pre-centrifugation delay longer than 24 h had an IL16 concentration higher than 313 pg/mL, and an IL8 concentration higher than 125 pg/mL, respectively. EDTA plasma samples with a pre-centrifugation delay longer than 48 h had an IL16 concentration higher than 897 pg/mL, citrate plasma samples had an IL8 concentration higher than 21.5 pg/mL and serum samples had an IL8 concentration higher than 528 pg/mL. Conclusions: These robust and accurate tools, based on simple and commercially available ELISA assays can greatly facilitate qualification of serum and plasma legacy collections with undocumented pre-analytics.


2013 ◽  
Vol 20 (11) ◽  
pp. 1669-1674 ◽  
Author(s):  
Lucy Duncombe ◽  
Nicola J. Commander ◽  
Sevil Erdenlig ◽  
John A. McGiven ◽  
Judy Stack

ABSTRACTBrucella abortus, a smooth strain of the genusBrucella, is the causative agent of bovine brucellosis. To support the ongoing development of diagnostic tests for bovine brucellosis, the use of Protein Saver cards (Whatman) for bovine blood serum and plasma sample collection has been evaluated. These cards offer significant logistical and safety alternatives to transporting and storing liquid samples and may aid in diagnostic programs and validation studies. To evaluate the utility of these cards, 204 bovine blood serum samples fromBrucella-infected and noninfected animals were stored on and eluted from the Protein Saver cards. Anti-Brucellasmooth lipopolysaccharide (sLPS) antibody titers for the serum eluates were compared to those of the unprocessed original serum samples by indirect enzyme-linked immunosorbent assay (ELISA). The results showed a highly significant correlation between titers from the serum eluates and the unprocessed sera. Therefore, under these circumstances, serum eluates and unprocessed serum samples may be used interchangeably. Blood plasma from 113 mitogen-stimulated whole-blood samples was added to and eluted from the Protein Saver cards. The gamma interferon (IFN-γ) titers in the plasma eluates were compared to those of the unprocessed plasma samples obtained by IFN-γ ELISA. The results showed a significant correlation between the plasma eluates and the unprocessed plasma samples. To derive a signal in the plasma eluate, it was necessary to develop a novel and highly sensitive ELISA for the detection of IFN-γ. The serum samples stored on cards at room temperature over a 10-day period showed little variation in antibody titers. However, the plasma eluates showed a progressive loss of IFN-γ recovery over 10 days when stored at room temperature.


2014 ◽  
Vol 34 (2) ◽  
pp. 212-218 ◽  
Author(s):  
Rahul P. Patel ◽  
Madhur D. Shastri ◽  
Mohammad Bakkari ◽  
Troy Wanandy ◽  
Matthew D. Jose

IntroductionThe objective of this study was to investigate the stability of ceftazidime and cephazolin in a 7.5% icodextrin or pH neutral peritoneal dialysis (PD) solution.MethodsCeftazidime and cephazolin were injected into either a 7.5% icodextrin or pH neutral PD bag to obtain the concentration of 125 mg/L of each antibiotic. A total of nine 7.5% icodextrin or pH neutral PD bags containing ceftazidime and cephazolin were prepared and stored at 1 of 3 different temperatures: 4°C in a domestic refrigerator; 25°C at room temperature; or 37°C (body temperature) in an incubator. An aliquot was withdrawn immediately before (0 hour) or after 12, 24, 48, 96, 120, 144, 168 and 336 hours of storage. Each sample was analyzed in duplicate for the concentration of ceftazidime and cephazolin using a stability-indicating high-performance liquid chromatography technique. Ceftazidime and cephazolin were considered stable if they retained more than 90% of their initial concentration. Samples were also assessed for pH, colour changes and evidence of precipitation immediately after preparation and on each day of analysis.ResultsCeftazidime and cephazolin in both types of PD solution retained more than 90% of their initial concentration for 168 and 336 hours respectively when stored at 4°C. Both of the antibiotics lost more than 10% of the initial concentration after 24 hours of storage at 25 or 37°C. There was no evidence of precipitation at any time under the tested storage conditions. Change in the pH and color was observed at 25 and 37°C, but not at 4°C.ConclusionPremixed ceftazidime and cephazolin in a 7.5% icodextrin or pH neutral PD solution is stable for at least 168 hours when refrigerated. This allows the preparation of PD bags in advance, avoiding the necessity for daily preparation. Both the antibiotics are stable for at least 24 hours at 25 and 37°C, permitting storage at room temperature and pre-warming of PD bags to body temperature prior to its administration.


1997 ◽  
Vol 33 (2) ◽  
pp. 149-155 ◽  
Author(s):  
A. E. OSMAN ◽  
F. GHASSALI

Two shrub species, Atriplex halimus L. and Salsola vermiculata L., are considered useful for rehabilitation of degraded rangelands in west Asia and north Africa. They can be established from direct seeding and are capable of self-sowing. In this study, seed storage at different temperatures and the influence of fruiting bracts on seed germination were examined for the two species during two seasons. Fruits (utricles) were stored at 20–22°C (room temperature), 0°C or −22°C. Germination tests were carried out after 33, 56, 90, 152, 272 and 397 d in storage in the first season and after 44, 76, 104, 170, 288 and 412 d in the second season. Seeds were germinated in their fruiting bracts or after bract removal. Bract removal significantly improved seed germination of both shrubs regardless of storage temperature. For S. vermiculata the increase in germination was in the range of 1.3- to 14.7-fold compared with values for the intact fruit in Season 1 and 0.5 to 3.8 in Season 2. Similarly the ranges for A. halimus were 0.5- to 4.2-fold and 0.7- to 5.3-fold in the two seasons respectively. The effect of cold storage was greater on Salsola than on Atriplex. The reduction of the storage temperature from 21°C to 0°C and −22°C increased the longevity of S. vermiculata seeds by 2.8–46.6 times in Season 1 and by 2.9–2.6 times in Season 2. There was little or no effect on the longevity of A. halimus. A leachate prepared by soaking fruiting bracts from S. vermiculata significantly depressed germination (p < 0.01), the effect being greater on Salsola seeds (20% reduction) than on Atriplex seeds (8% reduction). A leachate from A. halimus produced a slight but non-significant reduction in germination.


1997 ◽  
Vol 31 (9) ◽  
pp. 992-995 ◽  
Author(s):  
Montserrat Pujol ◽  
Montserrat Muñoz ◽  
Josefina Prat ◽  
Victoria Girona ◽  
Jordi De Bolós

Objective To determine the stability of epirubicin in NaCl 0.9% injection under hospital storage conditions. Methods NaCl 0.9% solution was added to epirubicin iyophilized powder to make a final concentration of 1 mg/mL to study the degradation kinetics and 2 mg/mL to study the stability in polypropylene syringes under hospital conditions. Setting Physical chemistry laboratory, Unitat de Fisicoquímica, Universitat de Barcelona. Main outcome Measures Solutions of epirubicin at 2 mg/mL in NaCl 0.9% solutions stored in plastic syringes were studied under hospital conditions at room temperature (25 ± 1 °C) and under refrigeration (4 ± 1 °C) both protected from light and exposed to room light (~50 lumens/m2). All samples were studied in triplicate and epirubicin concentrations were obtained periodically throughout each storage/time condition via a specific stability-indicating HPLC method. To determine the degradation kinetics, solutions of epirubicin in NaCl 0.9% at 1 mg/mL were stored at different temperatures (40, 50, and 60 °C) to obtain the rate degradation constant and the shelf life at room temperature and under refrigeration. Results The degradation of epirubicin in NaCl 0.9% solutions follows first-order kinetics. The shelf life was defined as the time by which the epirubicin concentration had decreased by 10% from the initial concentration. In this study, epirubicin was stable in NaCl 0.9% injection stored in polypropylene containers for all time periods and all conditions. That results in a shelf life of at least 14 and 180 days at 25 and 4 °C, respectively. The maximum decrease in epirubicin concentration observed at 25 °C and 14 days was 4%, and at 4 °C and 180 days was 8%. The predicted shelf life obtained from the Arrhenius equation was 72.9 ± 0.2 and 3070 ± 15 days at 25 and 4 °C, respectively, in both dark and illuminated conditions. Conclusions Solutions of epirubicin in NaCl 0.9% at 2 mg/mL are chemically stable when they are stored in polypropylene syringes under hospital storage conditions. No special precaution is neccessary to protect epirubicin solutions (2 mg/mL) from light.


2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 289-290
Author(s):  
Grace M Wesson ◽  
Lohana Fernandez ◽  
Rebecca K Poole ◽  
Gessica A Franco ◽  
Sydney T Reese ◽  
...  

Abstract Pregnancy associated glycoproteins (PAG) can be used as a biomarker for early pregnancy diagnosis, so accurate and consistent PAG detection is critical. The objective of this study was to determine if plasma and serum PAG concentrations were altered when centrifugation occurred at different times post-collection, when subjected to repeated freezing and thawing, and when monoclonal antibodies were kept in frequently or infrequently opened containers. Plasma (n = 4) and serum (n = 4) samples were collected from two open cows and two pregnant cows 28 days after artificial insemination. Pregnancy status was determined via transrectal ultrasonography. Plasma and serum samples were evenly separated and either centrifuged on the day of collection, or placed at 4°C and centrifuged the next day. An in-house PAG ELISA was performed on all samples before freezing (NOTHAW), after being frozen for one week (INTACT), after one freeze/thaw cycle (THAW1), two freeze/thaw cycles (THAW2), and three freeze/thaw cycles (THAW3). Data were analyzed using one-way ANOVA (GLM procedure, SAS 9.4). All samples from open cows were below the baseline of the assay. For pregnant cows, plasma samples had greater PAG concentrations than serum samples (11.84 vs 3.30 ± 0.66 ng/mL, respectively, P &lt; 0.05). No differences were observed for day of centrifugation in both plasma and serum samples (P = 0.50 and P = 0.60, respectively) and in handling of monoclonal antibodies (P = 0.90). Freezing and thawing did not impact PAG concentrations in plasma samples (P = 0.19), but did alter serum concentrations (P = 0.01). Specifically, THAW1 (1.98 ng/mL) and THAW2 (1.42 ng/mL) serum PAG concentrations were lower compared to NOTHAW, THAW3, and INTACT samples (4.66, 4.85, and 3.57 ng/mL, respectively). Based on these data, plasma yields more consistent results than serum, even after several freeze-thaw cycles, and handling of monoclonal antibodies or time of centrifugation has no significant effect on measured PAG.


Author(s):  
Toshiko Aiso ◽  
Shu Takigami ◽  
Akiko Yamaki ◽  
Hiroaki Ohnishi

Background Numerous studies demonstrate the potential of circulating microRNAs as non-invasive biomarkers for several diseases. Circulating microRNAs are much more stable than mRNAs and remain largely intact even after prolonged incubation at room temperature. However, recent reports show that microRNAs in serum or plasma samples have diverse stabilities. The aim of this pilot study is to evaluate the stabilities of miR-92a, miR-122 and miR-145 in serum during transient storage at 4℃ before freezing. Methods Serum samples were stored for 24 h at 4℃, and then RNA was extracted from whole serum or extracellular vesicles in serum. Total Exosome Isolation Reagent (from serum) was used for the fractionation of extracellular vesicles. Reverse transcription and real-time PCR of microRNAs were performed using the TaqMan MicroRNA Assays for miR-92a, miR-122 and miR-145. Results MiR-122 and miR-145 were degraded rapidly in serum; the concentrations dropped to 35.9% ( P < 0.001) and 29.3% ( P < 0.0001), respectively. These microRNAs in extracellular vesicles exhibited similar instability; the concentrations were 52.2% ( P < 0.05) and 56.5% ( P < 0.01), respectively. On the other hand, no significant degradation of miR-92a was observed (whole serum: P = 0.052, extracellular vesicles: P = 0.196). Conclusions MiR-122 and miR-145 in serum are extremely unstable and could be degraded during transient storage of serum at 4℃ prior to freezing.


2013 ◽  
Vol 85 (2) ◽  
pp. 761-768 ◽  
Author(s):  
ROSILDA M. MUSSURY ◽  
SILVANA P.Q. SCALON ◽  
MAGAIVER A. SILVA ◽  
TATIANE F. SILVA ◽  
HELLEN GOMES ◽  
...  

This paper aimed to evaluate the effects of storage periods on the conservation of Pachyrhizus ahipa roots at different temperatures and packaging materials. The roots were harvested, washed, packed in PVC, plastic bags, without wrappings (control) and stored in polystyrene trays in refrigerators, or cold chambers, or at room temperature. Total titratable acidity (TTA), total soluble solids (TSS), pH, as well as their ash, lipid, total carbohydrate and protein (dry basis) contents were analyzed. The lowest loss of root fresh weight was observed in the cold chamber and plastic bags. The TTA remained higher among roots stored in the cold chamber and in PVC packaging. The lowest TSS contents were observed for roots stored in the cold chamber, and these did not vary among the packing materials. The average carbohydrate content percentage for all treatments was 84.9%. The percentage of lipids was highest in roots stored at room temperature while protein and ash contents were highest in roots under refrigeration. The best storage conditions for roots are plastic bags packaging in a cold chamber, with the roots retaining appropriate quality for commercialization for up to 30 days.


1992 ◽  
Vol 38 (9) ◽  
pp. 1873-1877 ◽  
Author(s):  
D S Sgoutas ◽  
T Tuten

Abstract We studied the effect of freezing and thawing of serum on the determination of lipoprotein(a) [Lp(a)] with a commercial enzyme-linked immunosorbent assay (ELISA) and an immunoturbidimetric assay (ITA). Portions of sera from 11 apparently healthy persons and pooled sera, from an additional 10 subjects were frozen at either -20 or -70 degrees C and thawed at room temperature. Cycles of freezing and thawing were repeated during the experiments (1 month). Samples were assayed for Lp(a) after thawing. Pooled sera were subjected to quick freezing at -70 degrees C and thawing at room temperature in cycles. Results show a significant (P less than 0.05) decrease in Lp(a) concentration in sera subjected to freezing and thawing. Samples thawed from -20 degrees C gave concentrations by ELISA that were significantly lower than those of fresh samples after one freeze-thaw cycle. By ITA the decrease was significant only after two cycles. In specimens frozen at -70 degrees C, Lp(a) concentrations determined by ELISA decreased after two cycles, and by ITA after three freeze-thaw cycles. Serum samples subjected to quick freezing at -70 degrees C and thawing did not show significant decreases in Lp(a) immunoreactivity during four cycles. Immunoreactivity of Lp(a) in samples stored at 4 degrees C decreased after 6 days but fell faster in serum samples subjected to freezing and thawing before storage at 4 degrees C.


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