To mix or not to mix venous blood samples collected in vacuum tubes?

Author(s):  
Anna Parenmark ◽  
Eva Landberg

AbstractThere are recommendations to mix venous blood samples by inverting the tubes immediately after venipuncture. Though mixing allows efficient anticoagulation in plasma tubes and fast initiation of coagulation in serum tubes, the effect on laboratory analyses and risk of haemolysis has not been thoroughly evaluated.Venous blood samples were collected by venipuncture in vacuum tubes from 50 patients (10 or 20 patients in each group). Four types of tubes and 18 parameters used in routine clinical chemistry were evaluated. For each patient and tube, three types of mixing strategies were used: instant mixing, no mixing and 5 min of rest followed by mixing.Most analyses did not differ significantly in samples admitted to different mixing strategies. Plasma lactate dehydrogenase and haemolysis index showed a small but significant increase in samples omitted to instant mixing compared to samples without mixing. However, in one out of twenty non-mixed samples, activated partial thromboplastin time was seriously affected.These results indicate that mixing blood samples after venipuncture is not mandatory for all types of tubes. Instant mixing may introduce interference for those analyses susceptible to haemolysis. However, tubes with liquid-based citrate buffer for coagulation testing should be mixed to avoid clotting.

Life ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1125
Author(s):  
Alexandre Marchand ◽  
Ingrid Roulland ◽  
Florian Semence ◽  
Olof Beck ◽  
Magnus Ericsson

To combat the COVID-19 pandemic, vaccines against SARS-CoV-2 are now given to protect populations worldwide. The level of neutralizing antibodies following the vaccination will evolve with time and vary between individuals. Immunoassays quantifying immunoglobulins against the viral spike (S) protein in serum/plasma have been developed, but the need for venous blood samples could limit the frequency and scale of control in populations. The use of a quantitative dried blood spot (DBS) that can be self-collected would simplify this monitoring. The objective of this study was to determine whether a quantitative DBS device (Capitainer qDBS 10 µL) could be used in combination with an Elecsys anti-SARS-CoV-2 S immunoassay from Roche to follow the development and persistence of anti-S antibodies. This objective was carried out through two clinical studies. The first study investigated 14 volunteers who received two doses of the Comirnaty (Pfizer) vaccine. The levels of anti-S antibodies and the progression over time post-vaccination were studied for three months. The level of produced antibodies varied between subjects, but a similar trend was observed. The anti-S antibodies were highly stimulated by the second dose (×100) and peaked two weeks later. The antibody levels subsequently decreased and three months later were down to 65%. DBS proved to be sufficiently sensitive for use in evaluating the immune status against SARS-CoV-2 over a prolonged time. The second cohort was composed of 200 random patients from a clinical chemistry department in Stockholm. In this cohort, we had no information on previous COVID-19 infections or vaccination. Nevertheless, 87% of the subjects had anti-S immunoglobulins over 0.8 U/mL, and the bias between plasma and DBS proved to be variable, as was also seen in the first vaccination study.


1990 ◽  
Vol 259 (3) ◽  
pp. E397 ◽  
Author(s):  
A Virkamäki ◽  
I Puhakainen ◽  
N Nurjhan ◽  
J E Gerich ◽  
H Yki-Järvinen

To assess the validity of determining the origin of plasma lactate from the ratio of lactate and glucose specific activities (SA) during infusion of labeled glucose, normal subjects received infusions of [6-3H]- and [6-14C]glucose for 4 h after a 12 h fast, and, on another day, cold glucose labeled with both tracers during 4-6 h of hyperinsulinemia (approximately 650 microU/ml). Basally, less lactate was derived from plasma glucose when measured with [6-3H]glucose (27 +/- 2%) than with [6-14C]glucose (40 +/- 2%, P less than 0.001). Insulin did not increase the percent of lactate derived from plasma glucose when measured with [6-3H]glucose (29 +/- 2%) but did increase when measured with [6-14C]glucose (60 +/- 4%). The arterialized blood (A) [3H]lactate SA was 30-40% higher (P less than 0.01) than deep venous blood (V) [3H]lactate SA, whereas A and V [14C]lactate SA were similar. During conversion of alanine to lactate with glutamic-pyruvic transaminase (GPT) and lactate dehydrogenase (LDH) in vitro, 32 +/- 2% of 3H in [3-3H]alanine was found in water and 68 +/- 2% in lactate. During infusion of [6-3H]- and [6-14C]glucose, the ratio of [14C]alanine to lactate SA (0.88 +/- 0.05) was less than the ratio of [3H]alanine to lactate SA (0.31 +/- 0.03, P less than 0.001). In conclusion 1) loss of 3H relative to 14C from position 6 in glucose occurs during lactate formation in extrahepatic tissues possibly due to the GPT reaction (alanine conversion to pyruvate), and 2) even under supraphysiologic hyperinsulinemic conditions not all of plasma lactate originates from plasma glucose.


2019 ◽  
Vol 57 (12) ◽  
pp. 1888-1896 ◽  
Author(s):  
Martin H. Keppel ◽  
Simon Auer ◽  
Giuseppe Lippi ◽  
Alexander von Meyer ◽  
Michael Cornes ◽  
...  

Abstract Background Published evidence on the risk of additive carryover during phlebotomy remains elusive. We aimed to assess potential carryover of citrated and heparinized blood and the relative volume needed to bias clinical chemistry and coagulation tests. Methods We simulated standardized phlebotomies to quantify the risk of carryover of citrate and heparin additives in distilled water, using sodium and lithium as surrogates. We also investigated the effects of contamination of heparinized blood samples with increasing volumes of citrated blood and pure citrate on measurements of sodium, potassium, chloride, magnesium, total and ionized calcium and phosphate. Likewise, we studied the effects of contamination of citrated blood samples with increasing volumes of heparinized blood on heparin (anti-Xa) activity, lithium, activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT). We interpreted these results based on measurement deviations beyond analytical, biological and clinical significance. Results Standardized phlebotomy simulations revealed no significant differences in concentration of surrogate markers. Clinically significant alterations were observed after contamination of heparinized blood samples with volumes of citrated blood beyond 5–50 μL for ionized calcium and beyond 100–1000 μL for sodium, chloride and total calcium. Investigations of pure citrate carryover revealed similar results at somewhat lower volumes. Heparinized blood carryover showed clinically significant interference of coagulation testing at volumes beyond 5–100 μL. Conclusions Our results suggest that during a standardized phlebotomy, heparin or citrate contamination is highly unlikely. However, smaller volumes are sufficient to severely alter test results when deviating from phlebotomy guidelines.


Author(s):  
Giuseppe Lippi ◽  
Gian Luca Salvagno ◽  
Martina Montagnana ◽  
Giorgio Brocco ◽  
Gian Cesare Guidi

AbstractClin Chem Lab Med 2006;44:1009–14.


2020 ◽  
Vol 12 (1) ◽  
pp. 10-18
Author(s):  
Arsyam Mawardi ◽  
Hendra K. Maury ◽  
Yustinus Maladan

This study is aimed to analyze the comparative quality of PMSA2 gene amplicon product stability from two different specimen sources, spot specimens of dried blood and venous blood, as well as selecting the best storage method for specimens of blood samples. This research uses descriptive laboratory research methods. The research began with the process of sample preparation for dried blood spot and venous blood, each using Whatman 903 paper and vacuum tubes containing EDTA, isolating genomic DNA using KIT Zymo Research, amplification of PMSA-2 genes with PCR, detection of PCR products through electrophoresis, measurement of DNA concentration and absorbance, and data analysis. The results of this study are expected to be a source of information about the advantages of two specimen storage methods for clinical blood samples, as well as providing a clear description of the quality of each specimen storage method based on the quality of its amplicon products. The results showed that a total of ten medical samples of dried blood spot and ten venous blood were isolated from the genomic DNA of ten and nine, respectively. PMSA2 gene amplicons detected were seven in venous blood and six in dried blood spot. Venous blood specimens have sensitivity in detecting PMSA genes in samples with the highest value of 554 ng / μL and purity of 2,007 (WB7), and concentration of 550.2 and highest purity of 2,076 (WB10). Venous blood storage techniques using categorized vacuum tubes are effective in the detection of PMSA2 genes and have time efficiency in the process. From these results it was also concluded that the comparison analysis of amplicon products between venous blood specimens was better, more stable and efficient than dry blood spot specimens, thus recommending storage of venous blood specimens using vacuum tubes as the best storage method of blood sample specimens.


2012 ◽  
Vol 8 (3-4) ◽  
pp. 227-231 ◽  
Author(s):  
G. J. Stefánsdóttir ◽  
S. Ragnarsson ◽  
A. Jansson

Quick, simple methods for blood lactate analysis could be helpful in evaluating xercise response in the field, but methods validated for analysis of blood collected after high intensity exercise in horses are scarce. The aim of the present study was to compare the results obtained using a commercial, portable blood lactate analyser with those from laboratory plasma analysis of blood samples from horses performing intensive exercise. Venous blood samples were collected from 220 horses within 5 min of performing exercise at a mean peak heart rate of 222 ±9 beats/min. The samples were kept chilled and analysed using portable analyser within 10 min of collection. Samples were also centrifuged and the plasma frozen (-20 °C) until analysed using an enzymatic and spectrophotometric laboratory lactate analysis. There was a significant (P<0.05) correlation (R=0.94) between the methods at portable analyser values <12.0 mmol/l, but at higher values there was no correlation. There was a significant effect of method (P<0.0001) and portable analyser values were 21% lower than plasma lactate concentrations in the range 2.0-12.0 mmol/l. It is concluded that the portable analysis correlated well to a laboratory plasma analysis at portable analyser values <12.0 mmol/l and that the portable analyser appears to be a safe method for lactate analysis during training conditions, when very high lactate concentrations are not expected. However, users should be aware that the results underestimate the corresponding plasma values by approximately 20%.


1994 ◽  
Vol 3 (1) ◽  
pp. 16-22 ◽  
Author(s):  
CJ Laxson ◽  
MG Titler

How much blood must be discarded from a heparinized arterial line to obtain accurate coagulation studies, specifically activated partial thromboplastin time? The published literature provides insight into the question and guidelines for practice in adult critical care. This article reviews and integrates findings from 14 research studies published from 1971 to 1993 on discarding blood from arterial lines for coagulation studies. Investigators compared activated partial thromboplastin time values from arterial and venous blood samples using various discard volumes, sites and sizes of catheters, and heparin flush concentrations. Similarities and differences in arterial and venous activated partial thromboplastin time were reported. Studies have demonstrated that adequate discard volume for activated partial thromboplastin time is 6 times the catheter dead space. These results should not be generalized to systemically heparinized patients, pediatric patients, or other types of heparinized lines such as pulmonary artery, central venous, or Hickman catheters.


2012 ◽  
Vol 136 (10) ◽  
pp. 1262-1265 ◽  
Author(s):  
Marlies Oostendorp ◽  
Wouter W. van Solinge ◽  
Hans Kemperman

Context.—Elevated potassium concentrations due to in vitro hemolysis can lead to errors in diagnoses and treatment. Recently, we observed that potassium elevation in capillary samples appeared higher than expected, based on hemolytic index (H-index). Objective.—To investigate the relation between potassium increase and H-index for capillary samples. As a control, the same analysis was performed for lactate dehydrogenase (LDH). Design.—Potassium results of 332 760 venous and 2620 capillary samples were selected. For LDH, 135 974 venous and 999 capillary samples were included. Venous and capillary samples were differentiated by using patient age, as we perform mostly capillary blood sampling in children and venous sampling in adults. Results were obtained with Beckman-Coulter DxC800 analyzers. Results.—The increase in potassium with increasing H-index was considerably higher for capillary samples than venous samples. Linear regression revealed a potassium increase of 0.38 mEq/L per increment in H-index for capillary samples, whereas a 0.17 mEq/L increase was found for venous samples. For LDH, no differences were found between venous and capillary samples. Conclusions.—At identical H-index, capillary samples showed higher potassium elevations than venous samples. A possible explanation is that capillary sampling causes increased leakage of ions, such as potassium, from erythrocytes, compared with proteins such as hemoglobin and LDH. These results are especially important considering the increasing use of whole blood point-of-care analyzers, where the H-index is often not determined. Potassium results should therefore be interpreted with caution to avoid severe misdiagnosis of hypokalemia and hyperkalemia.


1994 ◽  
Vol 72 (05) ◽  
pp. 672-675 ◽  
Author(s):  
Nicolas W Shammas ◽  
Michael J Cunningham ◽  
Richard M Pomearntz ◽  
Charles W Francis

SummaryTo characterize the extent of early activation of the hemostatic system following angioplasty, we obtained blood samples from the involved coronary artery of 11 stable angina patients during the procedure and measured sensitive markers of thrombin formation (fibrino-peptide A, prothrombin fragment 1.2, and soluble fibrin) and of platelet activation ((3-thromboglobulin). Levels of hemostatic markers in venous blood obtained from 14 young individuals with low pretest probability for coronary artery disease were not significantly different from levels in venous blood or intracoronary samples obtained prior to angioplasty. Also, there was no translesional (proximal and distal to the lesion) gradient in any of the hemostatic markers before or after angioplasty in samples obtained between 18 and 21 min from the onset of the first balloon inflation. Furthermore, no significant difference was noted between angioplasty and postangioplasty intracoronary concentrations. We conclude that intracoronary hemostatic activation does not occur in the majority of patients during and immediately following coronary angioplasty when high doses of heparin and aspirin are administered.


1972 ◽  
Vol 28 (03) ◽  
pp. 383-392 ◽  
Author(s):  
J Hladovec ◽  
Z Koleilat ◽  
I Přerovský

SummaryThe venous occlusion of all four legs in rats caused a highly significant decrease of platelet counts in venous blood especially after the correction for an opposite change in haematocrit. A very pronounced decrease in platelets was observed in human volunteers after a venostasis in one arm in the blood drawn from the occluded limb just before the release of occlusion. Similar decreases were found after a venostasis of both legs in postocclusion blood samples. The decrease in blood platelets results from temporary sequestration in the occluded limbs. The decreases of platelets after a 10 min occlusion of both legs are more pronounced in patients with post thrombotic states.


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