Effect of pH and storage conditions on measured ionised calcium concentration in dogs and cats

2020 ◽  
Vol 187 (9) ◽  
pp. e72-e72
Author(s):  
Michal Mazaki-Tovi ◽  
Shira Topol ◽  
Itamar Aroch
Keyword(s):  
Calcium Concentration ◽  
Storage Conditions ◽  
Sample Collection ◽  
Serum Samples ◽  
Aerobic Conditions ◽  
Effect Of Ph ◽  
Ionised Calcium ◽  
Clinically Significant ◽  
And Storage ◽  
Good Agreement

BackgroundAerobic blood sample collection and processing results in increased serum pH and decreased ionised calcium (iCa) concentration. This prospective study aimed to determine the effect of pH and storage conditions on measured iCa concentration in serum samples obtained from dogs and cats and establish correction formulas for use in samples obtained aerobically.MethodsBlood samples were collected from 44 dogs and 25 cats; iCa and pH were measured immediately under anaerobic conditions and in samples stored under several aerobic conditions.ResultsMeasured iCa concentrations were significantly lower in samples stored at all aerobic conditions than in samples handled anaerobically in both dogs and cats (P<0.01 for all). The largest and most clinically significant differences were noted in samples stored at −20°C for 30 days in both dogs (0.48 mmol/l; 95 per cent CI 0.40 to 0.55) and cats (0.40 mmol/l; 95 per cent CI 0.33 to 0.47). Correction formulas (corrected iCa=measured iCa+coefficient × (measured pH–7.41); coefficient=0.597 for dogs, 0.627 for cats) yielded good agreement between the corrected and the actual iCa concentrations.ConclusionsSamples for iCa measurement can be stored at either 4°C or −20°C for 24 hours. Storage at −80°C is recommended for longer storage time periods.

scholarly journals Clinically Significant Effect of Protein Concentration on Ion-Selective Electrode Measurements of Ionised Calcium

1982 ◽  
Vol 19 (4) ◽  
pp. 233-237 ◽  
Author(s):  
R B Payne
Keyword(s):  
Plasma Proteins ◽  
Protein Concentration ◽  
Calcium Concentration ◽  
Human Albumin ◽  
Albumin Concentration ◽  
Selective Electrode ◽  
Serum Samples ◽  
Ionised Calcium ◽  
Clinically Significant ◽  
Positive Interference

Others, using an Orion SS-20 ionised calcium analyser, noted that the ionised calcium concentration of a native serum sample was 8% greater than that of its ultrafiltrate. The experiments described here, using a Nova 2 ionised calcium analyser, confirmed a positive protein interference which was greater for human albumin than for IgG. Uncharged dextran showed no positive interference but dextran sulphate, which is highly charged and binds calcium, showed a large effect. Thus the interference is related to macromolecule charge. Dialysis experiments with normal and pathological human serum samples indicated that the ionised calcium of diffusible plasma water was overestimated by an average of 9 · 6% at an albumin concentration of 40 g/l and by 4 · 8 % at 20 g/l. It is concluded that the measurement of ionised calcium with existing analysers can be clinically misleading in patients with abnormal plasma proteins. Hypocalcaemia is likely to be overdiagnosed and hypercalcaemia underdiagnosed in the presence of hypoalbuminaemia.

Variability in, variability out: best practice recommendations to standardize pre-analytical variables in the detection of circulating and tissue microRNAs

2017 ◽  
Vol 55 (5) ◽  
Author(s):  
Jenna Khan ◽  
Joshua A. Lieberman ◽  
Christina M. Lockwood
Keyword(s):  
Best Practice ◽  
Rna Extraction ◽  
Storage Conditions ◽  
Sample Collection ◽  
Ischemic Time ◽  
Cold Ischemic Time ◽  
C Storage ◽  
Tissue Specimens ◽  
And Storage

Abstract:microRNAs (miRNAs) hold promise as biomarkers for a variety of disease processes and for determining cell differentiation. These short RNA species are robust, survive harsh treatment and storage conditions and may be extracted from blood and tissue. Pre-analytical variables are critical confounders in the analysis of miRNAs: we elucidate these and identify best practices for minimizing sample variation in blood and tissue specimens. Pre-analytical variables addressed include patient-intrinsic variation, time and temperature from sample collection to storage or processing, processing methods, contamination by cells and blood components, RNA extraction method, normalization, and storage time/conditions. For circulating miRNAs, hemolysis and blood cell contamination significantly affect profiles; samples should be processed within 2 h of collection; ethylene diamine tetraacetic acid (EDTA) is preferred while heparin should be avoided; samples should be “double spun” or filtered; room temperature or 4 °C storage for up to 24 h is preferred; miRNAs are stable for at least 1 year at –20 °C or –80 °C. For tissue-based analysis, warm ischemic time should be <1 h; cold ischemic time (4 °C) <24 h; common fixative used for all specimens; formalin fix up to 72 h prior to processing; enrich for cells of interest; validate candidate biomarkers with in situ visualization. Most importantly, all specimen types should have standard and common workflows with careful documentation of relevant pre-analytical variables.

Effects of sample collection and storage conditions on DNA damage in buccal cells from agricultural workers

2011 ◽  
Vol 720 (1-2) ◽  
pp. 8-13 ◽  
Author(s):  
Juan F. Muniz ◽  
Linda A. McCauley ◽  
Victoria Pak ◽  
Michael R. Lasarev ◽  
Glen E. Kisby
Keyword(s):  
Dna Damage ◽  
Storage Conditions ◽  
Agricultural Workers ◽  
Sample Collection ◽  
Buccal Cells ◽  
And Storage

scholarly journals Effects of Temperature on Stability of Blood Homocysteine in Collection Tubes Containing 3-Deazaadenosine

2002 ◽  
Vol 48 (11) ◽  
pp. 2017-2022 ◽  
Author(s):  
Diane M Hill ◽  
Lisa J Johnson ◽  
Paul J Burns ◽  
Angela M Neale ◽  
Denise M Harmening ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Time Course ◽  
Hospital Setting ◽  
Storage Conditions ◽  
Effect Of Temperature ◽  
Sample Collection ◽  
Within Subjects ◽  
Effects Of Temperature ◽  
The Stability ◽  
And Storage

Abstract Background: The accuracy of homocysteine (Hcy) results is currently compromised by the requirement to separate the plasma within 1 h of sample collection. We studied the effect of temperature on the stability of plasma Hcy over a 72-h time course in blood collected into evacuated tubes containing either EDTA alone or both EDTA and 3-deazaadenosine (3DA). Methods: We recruited 100 volunteers, including both diseased and healthy individuals with a range of baseline plasma Hcy values, from two centers. Blood samples were collected into tubes containing EDTA, and EDTA plus 3DA and stored at ambient temperature (20–25 °C) or refrigerated (2–8 °C). Aliquots of blood were centrifuged at various times up to 72 h, the plasma was removed, and Hcy was measured by HPLC. Results: Plasma Hcy measurement covering the sample collection and storage conditions during the whole time course was possible on samples from 59 of those recruited. One-way ANOVA for repeated measures within subjects revealed that only samples that were collected into tubes containing EDTA plus 3DA and stored refrigerated were stable over 72 h (P = 0.2761). Conclusions: A combination of 3DA and storage at 2–8 °C will allow collection of samples for plasma Hcy measurement outside of the hospital setting and wider population screening.

scholarly journals Influence of Sample Type and Storage Conditions on Soluble CD40 Ligand Assessment

2006 ◽  
Vol 52 (5) ◽  
pp. 888-891 ◽  
Author(s):  
Michael Weber ◽  
Birgitt Rabenau ◽  
Michael Stanisch ◽  
Albrecht Elsaesser ◽  
Vesselin Mitrovic ◽  
...  
Keyword(s):  
Cd40 Ligand ◽  
Storage Conditions ◽  
Sample Type ◽  
Serum Samples ◽  
Soluble Cd40 Ligand ◽  
Coronary Syndromes ◽  
Edta Plasma ◽  
Few Data ◽  
The Impact ◽  
And Storage

Abstract Background: Several studies have consistently shown that soluble CD40 ligand (sCD40L) concentrations are increased in patients with acute coronary syndromes and can serve as a biomarker for risk stratification. However, few data are available on preanalytic conditions that impact sCD40L values. Thus, the aim of our prospective study was to evaluate the impact of sampling techniques and storage conditions on sCD40L concentrations. Methods: We included a total of 30 patients with no, stable, or unstable coronary heart disease. Blood samples were collected in gel-filled tubes without additives, in EDTA-filled tubes, and in citrate-filled tubes and were kept at various storage conditions. Results: Median (interquartile range) sCD40L values at baseline were higher in serum samples [5.29 (3.89–6.33) μg/L] than in either EDTA plasma [0.78 (0.39–1.12) μg/L; P &lt;0.001] or citrate plasma [0.37 (0.22–0.51) μg/L; P &lt;0.001]. Serum values increased with delayed processing [7.94 (5.97–9.62) μg/L after 1.5 h (P &lt;0.001) vs baseline; 10.55 (7.58–11.55) μg/L after 3 h (P &lt;0.001) vs baseline]. However, after centrifugation, sCD40L values remained stable for all 3 sample types. Conclusion: Plasma, but not serum, samples are appropriate for sCD40L measurements. In general, preanalytic conditions are critical in the assessment of sCD40L concentrations and thus should be carefully considered for future studies.

Effect of pH and storage conditions on Listeria monocytogenes growth inoculated into sapote mamey (Pouteria sapota (Jacq) H.E. Moore & Stearn) pulp

Food Control ◽  
2012 ◽  
Vol 28 (1) ◽  
pp. 110-117 ◽  
Author(s):  
Daniela Saucedo-Reyes ◽  
José Alfredo Carrillo-Salazar ◽  
María Isabel Reyes-Santamaría ◽  
Crescenciano Saucedo-Veloz
Keyword(s):  
Listeria Monocytogenes ◽  
Storage Conditions ◽  
Effect Of Ph ◽  
And Storage

scholarly journals Delivery of High-Quality Biomarker Assays

2002 ◽  
Vol 18 (2) ◽  
pp. 47-56 ◽  
Author(s):  
Brian N. Swanson
Keyword(s):  
Disease Process ◽  
Clinical Pathology ◽  
Storage Conditions ◽  
Quality Data ◽  
Sample Collection ◽  
High Quality ◽  
Exposure Response ◽  
Specificity And Sensitivity ◽  
Safety Studies ◽  
And Storage

Biomarker measurements now support key decisions throughout the drug development process, from lead optimization to regulatory approvals. They are essential for documenting exposure-response relationships, specificity and potency toward the molecular target, untoward effects, and therapeutic applications. In a broader sense, biomarkers constitute the basis of clinical pathology and laboratory medicine. The utility of biomarkers is limited by their specificity and sensitivity toward the drug or disease process and by their overall variability. Understanding and controlling sources of variability is not only imperative for delivering high-quality assay results, but ultimately for controlling the size and expense of research studies. Variability in biomarker measurements is affected by: biological and environmental factors (e.g., gender, age, posture, diet and biorhythms), sample collection factors (e.g., preservatives, transport and storage conditions, and collection technique), and analytical factors (e.g., purity of reference material, pipetting precision, and antibody specificity). The quality standards for biomarker assays used in support of nonclinical safety studies fall under GLP (FDA) regulations, whereas, those assays used to support human diagnostics and healthcare are established by CLIA (CMS) regulations and accrediting organizations such as the College of American Pathologists. While most research applications of biomarkers are not regulated, biomarker laboratories in all settings are adopting similar laboratory practices in order to deliver high-quality data. Because of the escalation in demand for biomarker measurements, the highly-parallel (multi-plexed) assay platforms that have fueled the rise of genomics will likely evolve into the analytical engines that drive the biomarker laboratories of tomorrow.

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