-
Blood Coagulation & Fibrinolysis : An... Jan 2021Coagulation assays, prothrombin time (PT), and partial thromboplastin time (PTT) are tests to measure the clotting ability of plasma and used in evaluating patients...
Coagulation assays, prothrombin time (PT), and partial thromboplastin time (PTT) are tests to measure the clotting ability of plasma and used in evaluating patients suffering from bleeding disorders. These assays require 100 μl of human plasma. In zebrafish, dilute plasma with exogenously added human fibrinogen was used. Our objective is to create a microkinetic coagulation assay for human and zebrafish plasmas using 1 μl plasma under conditions similar to PT and PTTs. Here, we developed an assay using the Take3 plate with wells holding up to 6 μl, which can be loaded in a microplate reader for measuring the absorbance of fibrin formation. In this assay, we used 1 μl of citrated zebrafish or human plasma followed by the addition of either thromboplastin or Dade ACTIN or factor X activator from Russell viper venom as an activating agent and CaCl2. We found 4 or 3 μl of the final volume of reaction was optimal. Our results showed both zebrafish and human plasmas yielded kinetic PT, kinetic PTT, and kinetic Russel's viper venom time curves similar to previously established curves using dilute plasma. This kinetic coagulation was inhibited by heparin and was reduced significantly in coagulation factor deficient plasmas. These results validated our microkinetic coagulation assays. Moreover, we derived clotting times from these kinetic curves, which were identical to human PT, PTT, and Russel's viper venom time. In conclusion, we established a microkinetic assay that could measure blood coagulation activity in models like zebrafish and human blood samples obtained from a finger prick in adults or heel prick in infants.
Topics: Animals; Blood Coagulation; Blood Coagulation Tests; Humans; Male; Microchemistry; Partial Thromboplastin Time; Plasma; Prothrombin Time; Zebrafish
PubMed: 33186131
DOI: 10.1097/MBC.0000000000000975 -
British Medical Journal (Clinical... May 1982
Topics: Administration, Oral; Anticoagulants; Humans; Prothrombin Time; Reference Standards; Thromboplastin; United Kingdom
PubMed: 6805548
DOI: 10.1136/bmj.284.6327.1425 -
Journal of Clinical Laboratory Analysis Jan 2015CoaguChek XS is one of the most widely used point-of-care (POC) devices to evaluate prothrombin time for monitoring oral anticoagulant therapy. Unlike laboratory... (Comparative Study)
Comparative Study
BACKGROUND
CoaguChek XS is one of the most widely used point-of-care (POC) devices to evaluate prothrombin time for monitoring oral anticoagulant therapy. Unlike laboratory methods, it detects electrical signals produced by thrombin activity to derive the international normalized ratio (INR). Therefore, we hypothesized that laboratory methods and CoaguChek XS could produce different results according to fibrinogen level.
METHODS
We compared INR values obtained from the CoaguChek XS and conventional laboratory method with 91 plasma samples covering a wide range of fibrinogen levels.
RESULTS
The samples were stratified into low, mid, and high fibrinogen groups by fibrinogen levels of <130 mg/dl, 130-450 mg/dl, and >450 mg/dl, respectively. The mean INR difference of the low fibrinogen group was significantly different from that of the mid or high fibrinogen group (P < 0.001). In the low fibrinogen group, CoaguChek XS INR showed a negative bias compared with the laboratory INR, while the mid and high fibrinogen groups had positive bias.
CONCLUSION
Our results suggest that patient selection according to fibrinogen status should precede the implementation of POC testing using CoaguChek XS. Also, periodic comparisons between CoaguChek XS and laboratory INR results should be continued during the use of CoaguChek XS.
Topics: Analysis of Variance; Blood Coagulation; Fibrinogen; Humans; International Normalized Ratio; Point-of-Care Systems; Prothrombin Time; Reproducibility of Results
PubMed: 24687901
DOI: 10.1002/jcla.21722 -
Computational and Mathematical Methods... 2022The mechanical heart valve is a crucial solution for many patients. However, it cannot function on the state of blood as human tissue valves. Thus, people with...
The mechanical heart valve is a crucial solution for many patients. However, it cannot function on the state of blood as human tissue valves. Thus, people with mechanical valves are put under anticoagulant therapy. A good measurement of the state of blood and how long it takes blood to form clots is the prothrombin time (PT); moreover, it is an indicator of how well the anticoagulant therapy is, and of whether the response of the patient to the drug is as needed. For a more specific standardized measurement of coagulation time, an international normalized ratio (INR) is established. Clinical testing of INR and PT is relatively easy. However, it requires the patient to visit the clinic for evaluation purposes. Many techniques are therefore being developed to provide PT and INR self-testing devices. Unfortunately, those solutions are either inaccurate, complex, or expensive. The present work approaches the design of an anticoagulation self-monitoring device that is easy to use, accurate, and relatively inexpensive. Hence, a two-channel polymethyl methacrylate-based microfluidic point-of-care (POC) smart device has been developed. The Arduino based lab-on-a-chip device applies optical properties to a small amount of blood. The achieved accuracy is 96.7%.
Topics: Anticoagulants; Computational Biology; Equipment Design; Heart Valve Prosthesis; Humans; International Normalized Ratio; Lab-On-A-Chip Devices; Optical Devices; Point-of-Care Testing; Polymethyl Methacrylate; Prothrombin Time; Self-Testing
PubMed: 35222684
DOI: 10.1155/2022/5975228 -
California Medicine Aug 1950Heparin is administered parenterally. Its therapeutic effect is measured by the clotting time of the whole blood, determined by the method of Lee and White. An excessive...
Heparin is administered parenterally. Its therapeutic effect is measured by the clotting time of the whole blood, determined by the method of Lee and White. An excessive anticoagulant effect is controlled by the administration of specific antagonists, toluidine blue or protamine sulfate. Dicumarol* is admintered orally in amounts sufficient to reduce the prothrombin activity of the plasma to between 10 and 30 per cent of normal. The prothrombin time, which represents such a reduction in prothrombin activity, will vary according to the method by which the determination is performed, the thromboplastin used, and the technique followed. Excessive prolongation of the prothrombin time is antagonized by the administration of vitamin K in large doses. Long-term therapy with Dicumarol is sufficiently hazardous to require considerable experience on the part of the physician. Where an immediate anticoagulant effect is necessary, yet prolonged administration anticipated, combined therapy with both heparin and Dicumarol may be used until the prothrombin time is prolonged satisfactorily, whereupon heparin may be discontinued.
Topics: Anticoagulants; Blood Coagulation Tests; Dicumarol; Heparin; Humans; Protamines; Prothrombin Time; Thromboplastin
PubMed: 15426992
DOI: No ID Found -
JAMA Internal Medicine Sep 2022This quality improvement study assesses changes in prothrombin time, international normalized ratio, and partial thromboplastin time testing after a best practices...
This quality improvement study assesses changes in prothrombin time, international normalized ratio, and partial thromboplastin time testing after a best practices advisory was issued.
Topics: Humans; International Normalized Ratio; Partial Thromboplastin Time; Prothrombin Time; Reference Standards
PubMed: 35849407
DOI: 10.1001/jamainternmed.2022.2609 -
Liver Transplantation : Official... Sep 2004The risks and benefits of adult-to-adult living donor liver transplantation need to be carefully evaluated. Anesthetic management includes postoperative epidural pain...
The risks and benefits of adult-to-adult living donor liver transplantation need to be carefully evaluated. Anesthetic management includes postoperative epidural pain relief; however, even patients with a normal preoperative coagulation profile may suffer transient postoperative coagulation derangement. This study explores the possible causes of postoperative coagulation derangement after donor hepatectomy and the possible implications on epidural analgesia. Thirty donors, American Society of Anesthesiology I, with no history of liver disease were considered suitable for the study. A thoracic epidural catheter was inserted before induction and removed when laboratory values were as follows: prothrombin time (PT) > 60%, activated partial thromboplastin time < 1.24 (sec), and platelet count > 100,000 mmf pound sterling (mm3). Standard blood tests were evaluated before surgery, on admission to the recovery room, and daily until postoperative day (POD) 5. The volumes of blood loss and of intraoperative fluids administered were recorded. Coagulation abnormalities observed immediately after surgery may be related mostly to blood loss and to the diluting effect of the intraoperative infused fluids, although the extent of the resection appears to be the most important factor in the extension of the PT observed from POD 1. In conclusion, significant alterations in PT and platelet values were observed in our patients who underwent uncomplicated major liver resection for living donor liver transplantation. Because the potential benefits of epidural analgesia for liver resection are undefined according to available data, additional prospective randomized studies comparing the effectiveness and safety of intravenous versus epidural analgesia in this patient population should be performed.
Topics: Adult; Anesthesia, Epidural; Blood Coagulation Disorders; Female; Hepatectomy; Humans; Linear Models; Liver Transplantation; Living Donors; Male; Middle Aged; Pain, Postoperative; Platelet Count; Postoperative Period; Prothrombin Time
PubMed: 15350005
DOI: 10.1002/lt.20235 -
Anesthesiology Feb 1994Although available hemostasis assays from institutional laboratories permit an analytical approach to diagnosis and treatment of coagulation disorders following... (Comparative Study)
Comparative Study
On-site prothrombin time, activated partial thromboplastin time, and platelet count. A comparison between whole blood and laboratory assays with coagulation factor analysis in patients presenting for cardiac surgery.
BACKGROUND
Although available hemostasis assays from institutional laboratories permit an analytical approach to diagnosis and treatment of coagulation disorders following cardiopulmonary bypass, their clinical utility has been limited by delays in obtaining results. The development of instrumentation for on-site testing allows rapid return of results. This study was designed to compare whole blood (WB) results obtained from on-site coagulation assays with values provided by our institutional laboratory (LAB).
METHODS
After Institutional Human Studies Committee approval, 362 patients presenting for cardiac surgery requiring cardiopulmonary bypass were enrolled in this study. Prothrombin time (PT), activated partial thromboplastin time (aPTT), and platelet count (PLT) assays were performed in both WB and LAB systems. PT, aPTT, and PLT measurements were compared between WB and LAB assays using blood specimens obtained from at least two time points for each patient. Normal range values for both PT and aPTT methods were determined by using measurements from a normal reference population. Coagulation factor levels were measured in a subset of patients to characterize the response of PT and aPTT assays to individual and multiple factor levels. To employ Bayes' theorem and calculate predictive indexes (e.g., sensitivity, specificity), the disease or factor deficiency was determined using factor levels. Predictive indexes were used to evaluate the ability of PT and aPTT assays to identify factor deficiency.
RESULTS
PLT counts were similar between systems. Linear regression and bias analysis demonstrated similar results for WB and LAB PT and discordant results for aPTT measurements. Both PT assays had a similar normal range, whereas a wider distribution of results was evident for the WB aPTT normal range. Although statistically greater slopes for factor:aPTT regressions were observed for the WB system, WB aPTT correlated better with factor V and with factor V, VIII, and XII levels (multivariate linear regression). Diagnostic performance for factor levels less than 0.3 and 0.4 U/ml was similar for both WB and laboratory PT and aPTT assays. WB and LAB PT and aPTT assays performed similarly in detecting factor deficiency in the period after cardiopulmonary bypass.
CONCLUSIONS
WB PT and PLT values correlate well with those obtained from the LAB. The discrepancy between measurement systems in aPTT values is probably a reflection of both different normal ranges and responsiveness to factor deficiency. These WB assays provide coagulation results that can accurately identify patients with quantitative deficiencies in platelets and coagulation factors.
Topics: Adult; Blood Coagulation Disorders; Blood Coagulation Factors; Cardiac Surgical Procedures; Cardiopulmonary Bypass; Clinical Laboratory Techniques; Humans; Partial Thromboplastin Time; Platelet Count; Prothrombin Time; Reference Values
PubMed: 8311316
DOI: 10.1097/00000542-199402000-00014 -
Polish Archives of Internal Medicine Jun 2018Direct oral anticoagulants (DOACs) do not require dose adjustment based on laboratory testing. However, it might be necessary to measure their plasma concentrations in... (Review)
Review
Direct oral anticoagulants (DOACs) do not require dose adjustment based on laboratory testing. However, it might be necessary to measure their plasma concentrations in the following specific situations: 1) before thrombolytic therapy in patients with stroke; 2) before surgery or invasive procedure; 3) in case of adverse events (thrombosis or hemorrhage); 4) when immediate reversal of anticoagulation is needed; 5) in patients with extreme body weight; 6) when administering additional drugs potentially interfering with DOACs; and 7) when overdosage is suspected regardless of concomitant bleeding. Basic coagulation tests, such as prothrombin and activated partial thromboplastin time, should not be used as standalone tests to assess the levels of anticoagulation as they are not specific for DOACs and their results are dependent on the type of reagent used for testing. Plasma DOAC concentrations should be assessed by dedicated tests: dilute thrombin time or ecarin tests (for dabigatran) or anti-factor Xa assays (for anti-factor Xa inhibitors). Dedicated tests should be calibrated against their respective plasma calibrators at certified DOAC concentrations and results should be expressed as ng/ml. Caution should be exerted when interpreting the results of the most common hemostatic parameters such as antithrombin, proteins C and S, lupus anticoagulant, or individual coagulation factors, as they may be strongly affected by the presence of a DOAC. Whenever possible, these parameters should be measured 4 to 5 days after discontinuation of DOAC anticoagulation.
Topics: Administration, Oral; Anticoagulants; Blood Coagulation; Blood Coagulation Tests; Humans; Practice Guidelines as Topic; Prothrombin Time; Thrombin Time
PubMed: 29968697
DOI: 10.20452/pamw.4287 -
British Medical Journal Oct 1954
Topics: Blood Coagulation; Coumarins; Hemorrhage; Hemostatics; Humans; Liver Diseases; Prothrombin; Prothrombin Time
PubMed: 13199356
DOI: 10.1136/bmj.2.4894.961