A Comparison of Two Sodium Citrate Concentrations in Two Evacuated Blood Collection Systems for Prothrombin Time and ISI Determination

2000 ◽  
Vol 84 (10) ◽  
pp. 664-667 ◽  
Author(s):  
V. Chantarangkul ◽  
A. Tripodi ◽  
A. M. H. P. van den Besselaar
Keyword(s):  
Prothrombin Time ◽  
Sodium Citrate ◽  
Oral Anticoagulant Therapy ◽  
Oral Anticoagulants ◽  
Practical Importance ◽  
Blood Collection ◽  
Blood Samples ◽  
Polyethylene Terephtalate ◽  
Glass Tubes ◽  
The Difference

SummaryThe prothrombin time is usually measured in citrated plasma. The W.H.O. recommended concentration of sodium citrate for blood collection for laboratory control of oral anticoagulant therapy is 0.109 M. Some evacuated blood collection systems include 0.105 M sodium citrate. The purpose of the present study was to establish the difference in ISI calibration between 0.109 and 0.105 M citrate, using 7 types of thromboplastin and various types of instrumentation. The two citrate concentrations were provided in both evacuated siliconised glass tubes and in evacuated polyethylene terephtalate (PET) tubes. The ISI difference between the two citrate concentrations was 5.4% for one system but not greater than 3% for all other systems when blood samples were collected with either siliconized glass or PET tubes. Most of the ISI differences between the two citrate concentrations were not significant at the 5% level. It is concluded that the ISI differences between 0.105 M and 0.109 M citrate are not of practical importance. In contrast, ISI differences between siliconised glass and PET tubes, using either 0.105 or 0.109 M citrate, were significant (p <0.05) for most thromboplastin systems and amounted to 7%. ISI interchange between these glass and PET tubes could induce INR differences amounting to 14%, which could affect clinical dosage of oral anticoagulants.

The Use of Evacuated Tubes for Blood Collection in Oral Anticoagulant Control

1983 ◽  
Vol 50 (03) ◽  
pp. 676-677 ◽  
Author(s):  
A M H P van den Besselaar ◽  
L P van Halem-Visser ◽  
E A Loeliger
Keyword(s):  
Prothrombin Time ◽  
Oral Anticoagulant ◽  
Oral Anticoagulant Therapy ◽  
Blood Collection ◽  
Anticoagulant Treatment ◽  
Contact Activation ◽  
Oral Anticoagulant Treatment ◽  
Blood Samples ◽  
Evacuated Tubes

SummaryThe prothrombin time (PT) test is used to monitor oral anticoagulant therapy. Contact activation of patient blood samples in vitro may shorten the PT and thus lead to underestimation of the degree of anticoagulation. Commercial evacuated tubes for blood collection have been reported to induce shortening of the PT. The Thrombotest modification of the PT determination was used to investigate the properties of different brands of evacuated siliconized tubes. Two recently manufactured batches of such tubes did not induce appreciable shortening of the PT and can therefore be recommended for use in monitoring oral anticoagulant treatment.

Prothrombin Time Ratio Is Reduced by Magnesium Contamination in Evacuated Blood Collection Tubes

2001 ◽  
Vol 85 (04) ◽  
pp. 647-650 ◽  
Author(s):  
W. van Dam ◽  
A. Sturk ◽  
R. M. Bertina ◽  
A. M. H. P. van den Besselaar
Keyword(s):  
Prothrombin Time ◽  
Sodium Citrate ◽  
Oral Anticoagulant Therapy ◽  
Blood Collection ◽  
Magnesium Ions ◽  
Time Ratio ◽  
Normal Plasma ◽  
The Mean ◽  
Blood Collection Tubes ◽  
Prothrombin Time Ratio

SummaryMagnesium ions were detected in sodium citrate solutions in several lots of evacuated blood collection tubes. The mean concentrations ranged between 1.3 and 1.6 mmol/L. Magnesium was also present in the rubber stoppers of the blood collection tubes and could be leached into the citrate solution. It was shown that magnesium added to citrated plasma shortened the prothrombin time of both coumarin and normal plasma. The effect of magnesium was relatively greater on coumarin than on normal plasma resulting in reduced prothrombin time ratio. Shortening of the prothrombin time was also observed when magnesium chloride was added to dialysed plasma, i.e., in the absence of citrate. These results indicate that magnesium contamination can interfere with accurate INR determination in the control of oral anticoagulant therapy.

1-Desamino-8-D-Arginine Vasopressin (DDAVP) Infusion in Type IIB von Willebrand’s Disease: Shortening of Bleeding Time and Induction of a Variable Pseudothrombocytopenia

1990 ◽  
Vol 64 (01) ◽  
pp. 117-120 ◽  
Author(s):  
Alessandra Casonato ◽  
M Teresa Sartori ◽  
Luigi de Marco ◽  
Antonio Girolami
Keyword(s):  
Monoclonal Antibody ◽  
Platelet Count ◽  
Arginine Vasopressin ◽  
Calcium Concentration ◽  
Sodium Citrate ◽  
Bleeding Time ◽  
Blood Collection ◽  
Von Willebrand's Disease ◽  
Blood Samples ◽  
Von Willebrand’S Disease

SummaryWe have investigated the effects of 1-desamino-8-D-arginine vasopressin (DDAVP) infusion on platelet count and bleeding time in 4 patients with type IIB von Willebrand’s disease (vWd). Three of four patients showed a normalization of the bleeding time within 1 h after the infusion, while bleeding time was not modified in the fourth. In accordance with the literature, thrombocytopenia was observed after DDAVP infusion, but this thrombocytopenia was due to the anticoagulants used for blood collection. In two patients (F. I., G. F.) no thrombocytopenia was observed when platelets were counted by fingerstick method but there was a 20% platelet decrease in blood samples collected in sodium citrate and a 50% decrease in samples collected in EDTA. Dramatic falls in platelet counts (70–95%) were observed in the additional two patients (C. A., D.Z.) after DDAVP infusion, when both sodium citrate or EDTA were used as anticoagulants. In the latter two patients there was also a 50% decrease in platelet count when the fingerstick method was used. The decrease in the patient’s platelet count in EDTA samples after DDAVP infusion could be prevented, in part, by the previous additions of an anti GPIb monoclonal antibody and an anti GPIIb-IIIa monoclonal antibody.Thus, the thrombocytopenia observed in the four IIB vWd patients studied after DDAVP infusion seems to be, at least partially, a pseudothrombocytopenia depending on the calcium concentration in the blood samples and the availability of GPIb and GPIIb-IIIa receptors. These findings and the normalization of the bleeding time observed in three of the four patients has led us to reconsider the possible use of DDAVP in the treatment of our IIB vWd patients.

The influence of exogenous magnesium chloride on the apparent INR determined with human, rabbit, and bovine thromboplastin reagents

2003 ◽  
Vol 89 (01) ◽  
pp. 43-47 ◽  
Author(s):  
Evelina Witteveen ◽  
Joyce Meeuwisse-Braun ◽  
Felix van der Meer ◽  
Anton van den Besselaar
Keyword(s):  
Magnesium Chloride ◽  
Sodium Citrate ◽  
Oral Anticoagulant Therapy ◽  
International Normalized Ratio ◽  
Bovine Brain ◽  
Rabbit Brain ◽  
Blood Collection ◽  
Bovine Plasma ◽  
Different Types ◽  
Blood Specimens

SummaryMagnesium ions can shorten the tissue factor-induced coagulation time. Some blood collection systems with sodium citrate are contaminated with variable amounts of magnesium and influence the results of the prothrombin time (PT) test. The aim of the study was to determine the dose-response relationship between exogenous magnesium chloride added to blood and the PT and the international normalized ratio (INR). Blood specimens from twenty patients on oral anticoagulant therapy were investigated. Four different types of thromboplastin reagents were used: recombinant human, human placenta, rabbit brain, and bovine brain combined with adsorbed bovine plasma. With all four reagents, exogenous magnesium induced a reduction of the apparent INR. Bovine thromboplastin was not as responsive to magnesium as the human and rabbit reagents. The magnitude of the INR deviation induced by 0.1 mmol/l magnesium in the blood was smaller than 10% in all patient samples. At 0.5 mmol/l magnesium in the blood, 10-35% of the patient samples had INR deviations greater than 10%, depending on the thromboplastin reagent used.

Some Effects of Purified Autoprothrombin C in Blood Clotting

1966 ◽  
Vol 16 (03/04) ◽  
pp. 707-722 ◽  
Author(s):  
G Müller-Berghaus ◽  
W. H Seegers
Keyword(s):  
Prothrombin Time ◽  
Partial Thromboplastin Time ◽  
Blood Clotting ◽  
Blood Stream ◽  
Clotting Time ◽  
Glass Tubes ◽  
Low Levels ◽  
The Difference ◽  
Autoprothrombin C ◽  
Stage Analysis

SummaryPurified autoprothrombin C was added to rabbit blood or recalcified plasma in order to measure the exact influence on clotting time. At a concentration of 10 u of autoprothrombin C per ml blood there was clotting in 13 sec. At that concentration recalcified plasma clotted in 7 to 8 sec. In the acceleration of the whole blood clotting time with autoprothrombin C, the effect was greater in glass tubes than in silicone coated tubes. The difference was probably due to lipids from platelets. With autoprothrombin C at a concentration of 10 u/ml reaction mixture, the prothrombin time and partial thromboplastin time of plasma was brought down to 3 to 4 sec. The partial thromboplastin time supplied the most sensitive conditions for detecting autoprothrombin C activity. Less than 2 × 10−5 micrograms of autoprothrombin C were detected. Rabbits that were treated with Coumadin had their prothrombin concentration reduced to 9 u/ml plasma, as measured by two-stage analysis. Such plasma yielded twice as much thrombin when purified autoprothrombin C and purified Ac-globulin were used in the assay to determine the thrombin potential. Even when the prothrombin concentration was brought to low levels with Coumadin a partial thromboplastin time or prothrombin time of 7 sec was easily obtained by using autoprothrombin C as procoagulant. The important effect of Coumadin or related drugs is the reduction of prothrombin concentration. This involves a lowering of the autoprothrombin C potential as well as the thrombin potential of plasma, and also the amount of inhibitor that can be obtained from prothrombin.Normal blood was found to contain prethrombin in small amounts as well as prothrombin. The synthesis of prothrombin was stopped with Coumadin and it is likely that the residual prothrombin was in part utilized by degradation to prethrombin, inhibitor and autoprothrombin III. At the height of the anticoagulant effect the prethrombin concentration was higher than the prothrombin concentration. With the resumption of prothrombin synthesis, when vitamin K was given, it may be that prethrombin, inhibitor, and autoprothrombin III was first produced in the liver and some of the latter entered the blood stream to compensate for substrate deficiency. Free autoprothrombin III would account for the short prothrombin time observed before prothrombin concentration rose.

USE OF INR FOR THE EXPRESSION OF PT IN PATIENTS UNDER ORAL ANTICOAGULANTS : COMPARISON OF RESULTS OBTAINED WITH FIVE THROMBOPLASTINS AND THREE DEVICES

1987 ◽  
Author(s):  
J H Roussi ◽  
D Francois ◽  
J Delemme ◽  
A F Goguel
Keyword(s):  
Prothrombin Time ◽  
Human Placenta ◽  
Oral Anticoagulants ◽  
International Normalized Ratio ◽  
The Other ◽  
Dilution Curve ◽  
Analysis Of Results ◽  
Student Test ◽  
The Difference ◽  
Normal Controls

The aim of our study is to know if INR (International Normalized Ratio) is really the best way to express PT (Prothrombin Time) in patients under oral anticoagulants (AVK). In this way, PT of 85 patients treated by AVK and 30 normal controls were determined with 5 different reagents and three devices : manual technic, KC10 (AHS Dade), Coag A Pet 200 (Gal Diagnostics, Organon). The reagents were : Thromborel S (Behring) extracted from human placenta, Thrombotest (Nyegaard) from ox brain, and 3 rabbit thromboplastins : Neo-plastine (Diagnostica Stago), Thromboplastine calcique (Bio-Merieux), Simplastin + (Gal Diagnostics). The results are expressed in seconds, percentage according to the dilution curve and INR with ISI given by the manufacturers.Analysis of results shows :- Influence of the technic : Whatever the technic is, mean results obtained with the same reagent, expressed in % are very close ; expressed in INR mean results are dispersed with all the reagents, ex :- Influence of the reagent : Results performed with the same technic whatever the reagent is expressed in INR are very close, whereas in % the dispersion is large.Analysis of variance and Student test show highly significant differences between all reagents for expression in %, whe reas expressed in INR (KC10) the difference is not statistical ly significant.INR leads an improvement in the dispersion of results but it seems necessary to have at least two ISI for each reagent, one determined by manual technic or device like KC10, the other one determined on photo-optical device.

scholarly journals Preanalytical Variables and Off-Site Blood Collection: Influences on the Results of the Prothrombin Time/International Normalized Ratio Test and Implications for Monitoring of Oral Anticoagulant Therapy

2005 ◽  
Vol 51 (3) ◽  
pp. 561-568 ◽  
Author(s):  
Johanna HH van Geest-Daalderop ◽  
André B Mulder ◽  
Leandra JM Boonman-de Winter ◽  
Martha MCL Hoekstra ◽  
Anton MHP van den Besselaar
Keyword(s):  
Prothrombin Time ◽  
Anticoagulant Therapy ◽  
Oral Anticoagulant ◽  
Room Temperature ◽  
Oral Anticoagulant Therapy ◽  
International Normalized Ratio ◽  
Blood Collection ◽  
Ratio Test ◽  
Mechanical Agitation ◽  
The Impact

Abstract Background: The quality of oral anticoagulant therapy management with coumarin derivatives requires reliable results for the prothrombin time/International Normalized Ratio (PT/INR). We assessed the effect on PT/INR of preanalytical variables, including ones related to off-site blood collection and transportation to a laboratory. Methods: Four laboratories with different combinations of blood collection systems, thromboplastin reagents, and coagulation meters participated. The simulated preanalytical variables included time between blood collection and PT/INR determinations on samples stored at room temperature, at 4–6 °C, and at 37 °C; mechanical agitation at room temperature, at 4–6 °C, and at 37 °C; time between centrifugation and PT/INR determination; and times and temperatures of centrifugation. For variables that affected results, the effect of the variable was classified as moderate when &lt;25% of samples showed a change &gt;10% or as large if &gt;25% of samples showed such a change. Results: During the first 6 h after blood collection, INR changed by &gt;10% in &lt;25% of samples (moderate effect) when blood samples were stored at room temperature, 4–6 °C, or 37 °C with or without mechanical agitation and independent of the time of centrifugation after blood collection. With one combination of materials and preanalytical conditions, a 24-h delay at room temperature or 4–6 °C had a large effect, i.e., changes &gt;10% in &gt;25% of samples. In all laboratories, a 24-h delay at 37 °C or with mechanical agitation had a large effect. We observed no clinically or statistically relevant INR differences among studied centrifugation conditions (centrifugation temperature, 20 °C or no temperature control; centrifugation time, 5 or 10 min). Conclusions: We recommend a maximum of 6 h between blood collection and PT/INR determination. The impact of a 24-h delay should be investigated for each combination of materials and conditions.

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