Stability of lorazepam diluted in bacteriostatic water for injection at two temperatures

Lorazepam is commonly used to produce sedation in infants. As errors may occur with the measurement of small volumes of concentrated drugs, we studied the stability of lorazepam diluted from 4 mg/ml to 1 mg/ml in bacteriostatic water for injection at two temperatures. The diluted lorazepam was stored in 10 glass vials (five at 22°C and five at 4°C). Samples were collected at 0, 7, 14, 28, 42, 56, 70 and 91 days after storage at each temperature. Lorazepam was measured in duplicate from each of five vials (n = 10) at each temperature by a specific and stability–indicating high–performance liquid chromatographic (HPLC) method. After 7 days' storage, the mean lorazepam concentration was 88% of the original concentration at 22°C, and 90% of the original concentration at 4°C. After 2 weeks of storage, the mean lorazepam concentration was 42% of the original concentration at 22°C, and 15% of the original concentration at 4°C. Crystals appeared after 4 weeks of storage at 22°C and after 2 weeks of storage at 4°C. At 3 months the mean lorazepam concentration was 6–1% and 7–5% of the original concentration at 22°C and 4°C, respectively. Thus, lorazepam diluted in bacteriostatic water for injection and stored in glass vials is stable for less than 7 days at 22°C and for 7 days at 4°C.     

Proper zinc evaluation in clinical practice: Effect of sample type and it's stability

Zinc (Zn) is a ubiquitous element that plays a vital role in the growth and development of human body. Traditionally, Zn has been measured in plasma samples using “trace element” dedicated sampling tubes. However, the recent increase in its assessment leads to the need to use others than plasma samples and the use of sera could be a justified and valid alternative. We evaluated the differences between plasma and serum, for Zn quantification. 307 blood paired samples from patients enrolled for the treatment of obesity-related pathology at our out-patient department were assessed. The quantification of Zn was performed by Flame atomic absorption spectroscopy. Using 123 serum samples randomly selected from our own biobank and stored at −80 °C for 5 years, we further investigated the long-term stability of serum Zn. The mean result for Zn was 77.8 ± 13.2 μg·dL⁻¹ and 77.4 ± 12.8 μg·dL⁻¹, respectively for plasma and for serum, (p = 0.43). Bland-Altman analyses demonstrated excellent concordance of the assay in the two different blood matrices. The mean difference ± SD between serum and plasma matrices was 0.32 ± 3.40 μg·dL⁻¹. The assessment of serum Zn long-term stability indicated a significant change after 5 years storage. The mean value was 74.2 ± 10.9 μg·dL⁻¹ for fresh samples and 83.3 ± 10.9 μg·dL⁻¹ after 5 years of storage at −80 °C, corresponding to a mean difference of +9.1 μg·dL⁻¹(+10,9%, p < 0.05). The increase in Zn values described after long-term storage has to be considered though that should not have a significant clinical value. In conclusion, the routine measurement of Zn can be made in an accurate way using a serum sample, without the need for a specific tube for trace elements assessment.     

β-Lactam stability in frozen microdilution PASCO MIC panels using strains with known resistance mechanisms as biosensors

The stability of amoxicillin/clavulanate, piperacillin/tazobactam, cefepime, imipenem, and meropenem in PASCO (PASCO System, DIFCO Laboratories, Detroit, MI, USA) frozen microdilution susceptibility panels stored for 16 weeks at −20°C and −70°C was evaluated. The increase in MIC values for the five American-Type Culture Collection (ATCC) quality control strains for susceptibility testing recommended by the National Committee for Clinical Laboratory Standards (NCCLS) and for 13 strains with different well-characterized resistance mechanisms was indicative of bioactivity deterioration. The overall agreement (±1 twofold dilution) at purchase between the MIC values of PASCO frozen microdilution susceptibility panels and the standard agar dilution method was 97.7%. Minimum inhibitory concentration values for the associations of amoxicillin/clavulanate and piperacillin/tazobactam remained unchanged for the study period at −70°C. In contrast, a carbapenem bioactivity decrease was detected only with strains having well-characterized resistance mechanisms from the 12th week onwards. At −20°C, antibiotic deterioration with these latter strains was observed earlier than with ATCC strains: the activity of meropenem and imipenem remained unchanged only for the first 2 weeks, while a loss of activity was detected for amoxicillin/clavulanate and piperacillin/tazobactam at the 7th and 10th week, respectively. Cefepime was highly stable both at −20°C and −70°C. Strains with well-characterized resistance mechanisms should be used in routine quality control studies of antibiotic stability for susceptibility testing panels during the storage period.     

Sample stability of autoantibodies: A tool for laboratory quality initiatives

ObjectivesSerum autoantibody measurement aids in diagnosing and monitoring various autoimmune conditions. Defining autoantibody stability limits can improve laboratory process quality. Here, we define short-term stability in a refrigerator, long-term stability in a freezer, and the effect of freeze–thaw cycles to improve autoantibody testing procedures.Design and methodsSeventy-nine residual serum samples were used to assess the stability of 11 autoantibodies (anti-dsDNA, anti-Ro52, anti-Ro60, anti-SSB, anti-RNP, anti-Sm, anti-aCL-IgG, anti-tTG-IgA, anti-tTG-IgG, anti-DGP-IgA, anti-DGP-IgG) and two screening assays (CTD screen, ENA7 screen) on the BIO-FLASH (Inova Diagnostics). Three storage conditions were assessed: 8 weeks at 2–8 °C, 12 months at −30 °C, and 6 freeze (−30 °C)-thaw cycles. The maximum permissible instability (MPI) for each autoantibody was set as 2x %CV, calculated as the weighted average CV from cumulative QC data over the study period.ResultsBy considering both mean percent difference (MPD) and mean absolute relative difference (MARD), all autoantibodies were stable for up to 8 weeks stored at 2–8 °C, except for CTD screen and anti-dsDNA. All autoantibodies were stable for up to 12 months stored at −30 °C, except ENA screen, anti-dsDNA, anti-DGP-IgA, anti-cardiolipin, and CTD screen. Lastly, all autoantibodies were stable for up to 6 freeze(−30 °C)-thaw cycles, except anti-RNP, anti-Ro60, anti-cardiolipin and anti-dsDNA.ConclusionsIt is important to develop laboratory procedures derived from evidence-based stability limits. This study will aid laboratories in undertaking quality assurance and improvement initiatives to enhance autoantibody testing by ensuring appropriate storage conditions that consider defined sample stability limits.     

Transregional autologous serum eye drop provision by a large German Red Cross Blood Donation Service

BackgroundThe Blood Donation Service West serves North Rhine-Westphalia (NRW), Rhineland-Palatinate (RP), and Saarland, an area of 56,500 km². In addition to routine red blood cell concentrates, plasma, and platelets, special products are provided. Since 2014, this has included autologous serum eye drops (ASED) for topical use in patients suffering from different illnesses accompanied by dry eye disease.MethodsA volume of 250–525 mL of patient blood was collected into an anticoagulant-free blood bag. Laboratory testing included Hepatitis B/C-, HIV 1/2-, and Lues-serology. Coagulation and centrifugation were followed by leukoreduction. Single-use vials were obtained by filling mini-bag systems using a sterile tube welder. Storage at ≤?20 °C enabled a shelf-life of up to 6 months and 30 days at 4 °C after thawing for shipment.ResultsContracts were closed with 15 ophthalmology clinics and medical practices in NRW and RP to supply patients with ASED. The patient pool increased from 19 in 2014 to 46 in 2020, with an average age of 43–55 years. Overall, blood collections almost tripled from 31 to 100 per year, increasing the stock of deliverable single-use vials from 3328 to 13,358. Delivery in a liquid state allowed engagement of 44 pharmacies located in the patient neighborhoods for continuous supply.ConclusionManufacturing in a closed bag system allowed integration into blood bank operations. However, cost-coverage by health insurance remained a case-by-case decision. Allogeneic application as ‘just-another-blood-product’ could be an aspiration. Yet, conclusive data from large clinical trials are needed for licensed provision in Germany.     

Effect of sample storage on stability of salivary glutathione,lipid peroxidation levels,and tissue factor activity

Saliva samples are often required to be stored for longer periods of time either because of the project protocol or because of lack of funding for analysis. The effects of 6 months storage (fresh, 30, 60, 90 120, 150, and 180 d) on the stability of salivary reduced glutathione (GSH), lipid peroxidation (LPO) and 90 days of storage (fresh, 15, 30, 60, and 90 d) on the stability of salivary tissue factor (TF) activity and the stability of saliva imprint samples at ?20°C were evaluated in this study. Salivary GSH, malondialdehyde (MDA) levels as an index of LPO, and TF activities were determined using the methods of Beutler, Yagi, and Quick, respectively. Saliva imprint samples were stained with Giemsa and microscopically examined. Salivary GSH levels and TF activities decreased, whereas MDA levels increased significantly after 6 months of storage at ?20°C. Leucocyte, epithelium and bacterium cell counts did not significantly change at the end of 90 d of storage. Saliva samples may be stored up to 1 month at ?20°C for LPO assay. For cytological examinations, saliva samples may be stored for 90 d at ?20°C. Further studies are needed to determine the stability of salivary GSH, and salivary TF activity stored less than 30 days at ?20°C. On the other hand, if saliva samples are required to be stored, to avoid the changes because of different storage periods, we recommend that they must be stored under the same circumstances and in the same time period. J. Clin. Lab. Anal. 23:93–98, 2009. © 2009 Wiley‐Liss, Inc.     

Long‐term stability of salivary cortisol

The measurement of salivary cortisol provides a simple, non‐invasive, and stress‐free measure frequently used in studies of the hypothalamic‐pituitary‐adrenal axis activity. In research projects, samples are often required to be stored for longer periods of time either because of the protocol of the project or because of lack of funding for analysis. The aim of the present study was to explore the effects of long‐term storage of samples on the amounts of measurable cortisol. Ten pools of saliva were collected on polyester Salivette^® tampons from five subjects. After centrifugation the samples were either stored in small vials or spiked to polyester Salivette tampons before analysis for cortisol using Spectria RIA kits. The effects of storage were evaluated by a linear regression model (mixed procedure) on a logarithmic scale. No effects on cortisol concentrations were found after storage of saliva at 5°C for up to 3 months or at ?20°C and ?80°C for up to one year. In contrast, concentrations of cortisol were found to decrease by 9.2% (95% confidence interval (CI): 3.8%; 14.3%) per month in samples stored at room temperature. Repeated freezing and thawing of samples up to four times before analysis did not affect the measured concentrations of cortisol. The coefficient of residual variation (CVresid) for samples stored on Salivette tampons were twice the CVresid for samples stored in separate vials after centrifugation. In conclusion, centrifuged saliva samples for analysis of cortisol may be stored at 5°C for up to 3 months or at ?20°C or ?80°C for at least one year. However, long‐term storage at room temperature cannot be recommended. Repeated cycles of freezing and thawing did not appear to affect the concentrations of cortisol.     

Long‐term stability of serum components in the Janus Serum Bank

Objective. Biobank material is frequently used in epidemiological studies, but long‐term storage of serum at ?25°C may reduce the quality of the samples. Knowledge about the stability of components in biological samples is fundamental for the interpretation of such studies. Material and methods. We investigated the stability of seven biological components in serum samples stored at ?25°C for 25 and 2 years compared with 1‐month‐old samples. Specimens from 130 blood donors from each group were randomly selected among men without a cancer diagnosis during the follow‐up time. We compared the distribution, dispersion and localization of medians and means, and established reference intervals of the components. Results. The study demonstrated non‐significant and numerically small differences in the levels of sodium, calcium, iron and creatinine over time. Differences between mean values for uric acid (?7.6%), potassium (+26.4%) and bilirubin (?59.4%) between fresh and 25‐year‐old samples indicated that sample handling before freezing and degradation during long‐term storage may introduce a considerable bias for vulnerable components. Conclusions. There is large variation in level stability between different serum components in serum stored at ?25°C. Differences in sample handling before freezing may introduce bias on vulnerable components. The present study supports a routine of careful matching of cases and controls on storage time in epidemiological studies when biobank material is used.     

High sensitivity C-reactive protein (Hs-CRP) remains highly stable in long-term archived human serum

BackgroundThe stability of biomarkers in stored biomedical samples is crucial, especially when storage is for extended periods of time. High-sensitivity CRP (Hs-CRP) is a biomarker of low grade inflammation that is extensively used to identify and study cardiovascular and/or inflammatory processes in clinical care and large epidemiologic studies. Therefore, assessing Hs-CRP stability in archived samples at a given temperature is important to ensure precision of measurements over time and the validity of studies using archived samples.MethodsWe evaluated the stability of Hs-CRP in 30 randomly selected human serum samples by measuring Hs-CRP concentrations in freshly collected sample [Hs-CRP (0)] and in the same set of samples after 7–11 years of storage at − 80 °C [Hs-CRP (LT)].ResultsHs-CRP did not significantly change up to 11 years of storage at − 80 °C as shown by a negligible median difference between Hs-CRP (0) and Hs-CRP (LT), delta_{(Hs-CRP (0)–Hs-CRP (LT))} = − 0.01, p = 0.45. There was a good concordance and agreement between Hs-CRP (0) and Hs-CRP (LT) as measured respectively by Lin's coefficient of correlation (ρ_C = 0.98) and Bland–Altman analysis (mean difference = − 0.02, 95% CI [− 0.04–0.0045] p = 0.107). In addition, the data also suggest that the time elapsed between collection and Hs-CRP measurement does not affect Hs-CRP stability over time when samples are kept under the appropriate conditions.ConclusionsLong-term storage at − 80 °C for up to 11 years did not significantly affect the stability of serum Hs-CRP. Given the cost and time for collecting fresh samples, this observation represents an important finding for biomedical research and clinical care.     

Stability of blood analytes after storage in BD SST™ tubes for 12 mo

ObjectivesWe studied the stability of 33 analytes related to clinical chemistry, bone, and vitamin metabolism, after storage in serum separator tubes (SST?).Design and methodsBlood was collected from 6 subjects using SST tubes. Some serum remained in the tube in contact with the barrier gel and was stored at ? 80 °C for 12 mo.ResultsClinically significant changes occurred only in 1,25-dihydroxyvitamin D and retinol-binding protein.ConclusionsFreezing SST tubes before sample analysis is a viable option for some analytes.     

Stability of bortezomib 1-mg/mL solution in plastic syringe and glass vial

BACKGROUND: The proteasome inhibitor bortezomib (BTZ), used in antineoplastic chemotherapy, must be diluted in NaCl 0.9% for injection and stored for no more than 3 hours in a syringe or 8 hours in a vial. Better information on its stability could improve storage. OBJECTIVE: To assess the stability of BTZ solution (1 mg/mL) in syringes and vials. METHODS: BTZ 1-mg/mL solutions were prepared by adding sterile NaCl 0.9% to Velcade vials containing 3.5 mg of lyophilized BTZ. Syringes were filled with 1 mL of solution and stored in the dark at 5 degrees C or 60 degrees C; others were not protected from light and stored at 22 degrees C. Velcade vials containing 1 mL of solution were stored at 5 degrees C in the dark. Samples were taken at various times over 23 days and assayed in duplicate. An HPLC method for assaying the stability of BTZ was validated. Appearance and pH were recorded. RESULTS: There was no color change or precipitation in the samples, and the pH was stable. Oxidation, light, and storage temperature all affected the chemical stability of BTZ. The mean concentrations of BTZ in syringes stored for 2, 3, and 5 days at 60, 22, and 5 degrees C were >95% of the initial concentration. The mean concentration of BTZ in vials stored for 5 days at 5 degrees C was >95% of the initial concentration. CONCLUSIONS: BTZ stored refrigerated in vials or syringes and protected from light is chemically stable for 5 days after reconstitution.     

Adrenaline activity is not significantly altered by high ambient temperatures.

Drugs used in prehospital care are exposed to extremes of temperature, which exceed the manufacturerer's recommended storage conditions, and may result in degradation of the formulation. Adrenaline, which can be degraded by high temperatures, is a key agent for the effective management of cardiac arrest and acute anaphylaxis in the prehospital setting. We demonstrate that the activity of adrenaline vials carried in St John's ambulances in the Perth metropolitan area during summer months when ambient temperatures can reach 40°C was not significantly altered.     

Glucose variation in centrifuged serum and lithium-heparin gel tubes stored for up to 96 hours at room temperature or 4 °C

Abstract

This study aimed to verify glucose stability within centrifuged serum and lithium-heparin tubes stored at room temperature (RT) or 4?°C. Sixty paired serum (plus gel separator), lithium-heparin (plus gel separator) and K₂-EDTA tubes were centrifuged within 30?min from collection. Thirty serum and lithium-heparin tubes were then stored at RT, whilst the other 30 serum and lithium-heparin tubes were kept at 4?°C. Complete cell blood count was performed in serum and plasma after centrifugation, as well as in K₂-EDTA paired whole blood tubes. Glucose was measured immediately after centrifugation and 3, 6, 24, 48, 72 and 96?h afterwards. Immeasurable blood cells values were found in serum, whilst residual leukocytes and platelets were present in lithium-heparin plasma. Regardless of storage conditions, glucose concentration decreased 3?h after centrifugation in lithium-heparin tubes, displaying uninterrupted reduction until 96?h. Mean decrease per hour was higher in plasma tubes stored at RT than at 4?°C. Performance specification was exceeded between 6 and 24?h of storage in most plasma tubes. Glucose concentration significantly decreased in serum tubes between 24 and 48?h, regardless of storage conditions. The mean glucose variation never exceeded performance specification throughout the study period. Mean glucose decrease per hour in plasma was not associated with blood cells counts before and after centrifugation, and was probably attributable to the presence of blood cells entrapped within the gel. Delayed glucose measurement in centrifuged serum tubes may be clinically viable up to 96?h, whilst it may be unadvisable in centrifuged lithium-heparin tubes.     

Effect of freeze-thawing on the long-term stability of calcium levofolinate in 5% dextrose stored on polyolefin infusion bags

Background: Calcium levofolinate infusions could be prepared in advance by a centralized intravenous additive service (CIVAS) to improve safety and time management. Objective: To investigate the effect of freezing, microwave thawing and long‐term storage at 5 ± 3 °C on the stability of calcium levofolinate in 5% dextrose solution. Methods: Solutions of 250 mL of 5% dextrose in polyolefin bags (n = 5) containing approximately 400 mg of calcium levofolinate were prepared under aseptic conditions and frozen for 95 days at ?20 °C. The solutions were then thawed using microwaves and stored at 5 ± 3 °C for 1 month. The calcium levofolinate concentrations were measured by high performance liquid chromatography (HPLC). Visual inspection was performed and pH was measured periodically during the storage at 5 ± 3 °C. Stability of the solution was defined as a concentration remaining superior to 90% of the initial concentration by regression analysis as recommended by the Food and Drug Administration (FDA). Results: No colour change or precipitation in the solutions was observed. Calcium levofolinate infusions were stable when stored at 5 ± 3 °C during 1 month after freeze‐thaw treatment. Throughout this period, the lower confidence limit of the estimated regression line of concentration‐time profile remained above 90% of the initial concentration. Slight change in pH values from 6·52 ± 0·01 to 6·50 ± 0·01 during storage time did not affect retention time on HPLC and has no clinical consequence, the solutions remaining in the acceptable range for perfusion (4 ≤ pH ≤ 10). Conclusion: Under the conditions of this study, calcium levofolinate in 5% dextrose infusion may be prepared, frozen in advance by CIVAS, and then microwave thawed before use. Such treatment extends long‐term stability and releases pharmacist’s time for major activities such as checking medication order errors.     

Frozen for combat: Quality of deep-frozen thrombocytes,produced and used by The Netherlands Armed Forces 2001–2021

Background

The Netherlands Armed Forces (NLAF) are using −80°C deep-frozen thrombocyte concentrate (DTC) since 2001. The aim of this study is to investigate the effect of storage duration and alterations in production/measurement techniques on DTC quality. It is expected that DTC quality is unaffected by storage duration and in compliance with the European guidelines for fresh and cryopreserved platelets.

Study Design and Methods

Pre-freeze and post-thaw product platelet content and recovery were collected to analyze the effects of dimethyl sulfoxide (DMSO) type, duration of frozen storage (DMSO-1 max 12 years and DMSO-2 frozen DTC max 4 years at −80°C) and type of plasma used to suspend DTC. Coagulation characteristics of thawed DTC, plasma and supernatant of DTC (2× 2500 G) were measured with Kaolin thromboelastography (TEG) and phospholipid (PPL) activity assay.

Results

Platelet content and recovery of DTC is ±10%–15% lower in short-stored products and remained stable when stored beyond 0.5 years. Thawed DTC (n = 1724) were compliant to the European guidelines (98.1% post-thaw product recovery ≥50% from original product, 98.3% ≥200 × 10⁹ platelets/unit). Compared to DMSO-1, products frozen with DMSO-2 showed ±8% reduced thaw–freeze recovery, a higher TEG clot strength (MA 58 [6] vs. 64 [8] mm) and same ±11 s PPL clotting time. The use of cold-stored thawed plasma instead of fresh thawed plasma did not influence product recovery or TEG-MA.

Discussion

Regardless of alterations, product quality was in compliance with European guidelines and unaffected by storage duration up to 12 years of −80°C frozen storage.     

Effects of serum storage on the determination of cholesterol

Cholesterol determined by 4 different enzymatic commercial kits and by the dry chemistry Reflotron system was higher in serum stored at 4 °C and at −20 °C than in fresh serum. The effects of storage seem to be temperature-dependent. In fact, cholesterol values significantly increased only after 2h of freezing. The prolongation of freezing up to 2 weeks was not followed by further significant changes. In serum stored at 4 °C the increase in cholesterol was slower than in frozen serum. Both free and esterified cholesterol underwent an increase after storage. When cholesterol was determined by a chemical method (sulfuric acid-ferric chloride) after extraction with ethyl acetate and ethanol, no difference was observed in fresh and stored serum. Cholesterol, triglycerides and apoproteins A-I and B underwent parallel changes after storage both in whole serum and fractionated lipoproteins. Our findings strongly suggest that in serum stored at positive or negative temperature there is an alteration of the lipoprotein molecules which allows an easier availability of cholesterol for the enzyme-substrate reaction than in fresh serum. Current enzymatic methods underestimate (about 10%) cholesterol when the analysis is performed on fresh serum.     

Inhibition of cytokine accumulation and bacterial growth during storage of platelet concentrates at 4 degrees C with retention of in vitro functional activity

BACKGROUND : The potential for bacterial contamination limits the storage of platelet concentrates (PCs) at 22° C to 5 days. In addition, storage of platelets under conventional protocols for longer times (> 3 days), in the absence of white cell filtration, has been correlated with incidents of cytokine-associated febrile reaction in recipients. It has been demonstrated that the addition of a reagent mixture of second-messenger effectors allows platelets stored at 4°C to maintain significant in vitro functional activity. Thus, the effects of 4°C storage on the growth of bacteria and the accumulation of cytokines by the white cell fraction of PCs were analyzed to demonstrate the benefits of this refrigerated storage system. STUDY DESIGN AND METHODS : The platelet storage solution was added directly to PCs obtained from the blood bank, and these treated PCs were stored at 4° C without agitation. In parallel, control PCs were stored according to standard blood-banking procedures. On Days 1, 3, 5, and 9, the PCs were measured for the plasma concentrations of cytokines. Treated and control PCs stored at 4°C and 22°C were inoculated with low-titer Staphylococcus aureus, and bacterial growth was measured over a 5-day period. RESULTS : Control PCs displayed a time-dependent increase in the plasma concentration of interleukin 6, interleukin 1β, and tumor necrosis factor α. These conventionally stored PCs also displayed a time-dependent increase in the bacteria titer. In contrast, the treated PCs stored at 4°C displayed no accumulation of the above cytokines in the plasma fraction and no increase in bacteria titer above the initial inoculation. CONCLUSION : The storage of PCs at refrigerated temperatures inhibits the accumulation of white cell-produced cytokines in the PCs, an effect that could alleviate cytokine-associated febrile transfusion reactions The 4°C storage was also bacteriostatic, which indicates that the storage of PCs at that temperature increases safety by decreasing the potential for sepsis. Thus, the ability to store PCs at 4°C may allow extension of the storage limit beyond 5 days.     

Stability of coagulation factors in plasma prepared after a 24‐hour room temperature hold

BACKGROUND: The manufacture of fresh‐frozen plasma (FFP) requires that plasma be frozen within 8 hours of collection and 24‐hour frozen plasma requires 1 to 6°C refrigeration before freezing. Manufacture of plasma after a room temperature hold for 24 hours, while convenient, could compromise clotting factor levels. STUDY DESIGN AND METHODS: Pairs of FFP and 24‐hour room temperature–frozen plasma (PLT‐rich plasma [PRP]‐24HRTFP) were manufactured from PRP after a room temperature hold for 8 and 24 hours, respectively. Additional whole blood (WB) donations were kept at room temperature for 24 hours before plasma manufacture (WB‐24HRTFP). The frozen plasma products were stored at −18°C, thawed, and then stored at 1 to 6°C, with coagulation factor assays performed for up to 7 days. RESULTS: On the day of thaw, Factor (F)VIII was lower in PRP‐24HRTFP by 13% (p = 0.002) but not in WB‐24HRTFP (p = 0.3) compared to FFP. All other clotting factors were within normal range. During the postthaw period FVIII and FV declined 25 and 6%, respectively, in WB‐24HRTFP and 23 to 50% in the paired products; however, the difference between both types of 24HRTFP and FFP is insignificant by Day 7 (p > 0.05). Other clotting factors either were unchanged or showed minimal reduction (<15%). CONCLUSION: Plasma manufactured after a 24‐hour room temperature hold contains coagulation factors comparable to FFP except for a possible reduction of up to 20% in FVIII. This plasma appears suitable as a transfusable product and extension of liquid storage to 7 days merits consideration.     

Vitamin C in plasma: a comparative study of the vitamin stabilized with trichloroacetic acid or metaphosphoric acid and the effects of storage at -70 degrees, -20 degrees, 4 degrees, and 25 degrees on the stabilized vitamin

Vitamin C concentration in human plasma was shown to be affected by storage time and temperature as well as by the kind of stabilizer used. Samples were stored for periods of time up to 21 days at temperatures of 25°, 4°, ? 20°, and ? 70°. Stabilizers employed in this study included trichloroacetic acid (TCA) and metaphosphoric acid (MPA). Plasma vitamin C demonstrated maximum stability in TCA or MPA when stored at ? 70°. Other storage conditions tested yielded less accurate vitamin C values.