Instrumentation and Quality Control in Secondary Hemostasis PDF

Instrumentation and Quality Control in Secondary Hemostasis Presented by Group 2 What is Secondary Hemostasis? Secondary hemostasis is the process that stabilizes the initial platelet plug formed during primary hemostasis. It involves a cascade of coagulation factors that ultimatel...

Instrumentation and Quality Control in Secondary Hemostasis Presented by Group 2 What is Secondary Hemostasis? Secondary hemostasis is the process that stabilizes the initial platelet plug formed during primary hemostasis. It involves a cascade of coagulation factors that ultimately lead to the formation of fibrin, which reinforces the platelet plug and helps to form a stable blood clot. Secondary Hemostasis is essential for effective wound healing and maintaining hemostatic balance in the body. Understanding this process is critical for diagnosing and treating bleeding disorders and conditions associated with thrombosis. Secondary Hemostasis Pathway  Quality Control “Systematic MONITORING to detect ERRORS” Quality Control (QC) in a clinical laboratory plays an important role in detecting deficiencies and reducing errors in laboratory’s analytical process prior to the release of patient’s results. The purpose of quality control in the clinical laboratory is to ensure that the results being reported are accurate and precise. Internal Quality Control Internal quality control (IQC) is performed daily in the laboratory and involves the use of calibrated glassware, reagents and equipment. The laboratory staff should be qualified professionals. There is a recommendation to use atleast two control levels for each analyte. The samples are internally evaluated in the laboratory.  ACCURACY PRECISION - refers to how close a - ability of the test to measurement is to the true duplicate target. or accepted value. It represents the correctness of a measurement.  External Quality Control External quality control (EQC) or proficiency testing (PT) is performed as a test of competency. It includes the participation of the laboratory in an external quality assessment scheme which provides samples for analysis every month. They have to be analyzed by the laboratory professionals using the same procedures as used for testing of quality control sample and patient samples.  Quality Control Chart The Levey Jennings (L-J) Chart Westgard Rules The use of Levey Jennings chart It involves the use of multiple (L-J chart) is one of the most control rules which help in commonly used charts to monitor improving the performance quality control results. It is a of quality control. It also helps in graphical method for displaying deciding whether the analytical run the values of controls. is in control or out of control  Reagent Quality Control Criteria Reagent Compatibility - it is important that reagents selected be compatible with available instrumentations. This may be readily achieved by selecting reagents and equipment’s marketed by the same vendor. Cost - cost must be considered in light of budgetary constraints. When more than one reagent will perform satisfactory, a cost savings may be realized by requesting competitive bids from suppliers. Reproducibility - the results obtained with a given reagent may be determined by the laboratory or from examination of the results obtained by many laboratories on survey samples  Reagent Quality Control Criteria Sensitivity - in evaluating a reagent, the laboratory needs information regarding test system sensitivity to specific factor deficiencies because of its possible association with an increase incidence of thrombosis, there is considerable interest in the sensitivity of PTT reagents to the lupus anticoagulant. Purposes Used as routine screening tests for coagulation disorders, these tests may be used even more frequently to monitor anticoagulant therapy.  Quality Control REMEMBER: We run control materials so we can check the accuracy and precision of testing. So that we can make sure that the machines and reagents are in good condition. CONSIDERATIONS OF CONTROL MATERIAL USED To monitor precision To determine SD Run control materials: every after 20 tests. Coagulation Analyzers Coagulation Analyzer Definitions Categories Optical Coagulometers These analyzers measure changes in light transmission or absorbance as the blood clot forms. They are used for test like PT, APTT and fibrinogen assays. Viscoelastic These detects clot formation by instrumentation measures measuring the change in viscosity or movement of a metal ball as a clot forms.  Immunologic Light These assays rely on antigen-antibody reactions, Absorbance End-Point where latex microparticles coated with antibodies target specific antigens. Instead of using light Detection scattering like nepholometry, they detect the reaction’s end-point by measuring light absorbance as it passes through the suspension. Viscoelastic Clot The viscoelastic technique, still used in some Detection instruments for whole blood clotting, is not high- volume but remains relevant. Nephelometry used in modern automated coagulometers provides a quantitative assay of coagulation factors and supports multiple-assay profiles, including clot- based and immunoassays  These use electrical or light-based methods to monitor the development of Electromagnetic or the clot in the sample. Popular Nephelometric Analyzers coagulation analyzers for secondary hemostasis.  2 Different wire loops which acts as electrodes: 1. First loop is stationary 2. Second loop is moving Semi-automated detection used to eliminate the subjectivity because you let the machine/analyzer identify that there's already a clot. Note: Common mistake in Visual detection and Electromechanical detection, the reagents are not yet mixed but the timing is already started. = makes clotting time falsely elevated.  PHOTO - OPTICAL DETECTION - depends on the increase light scattering As soon as you formed a clot and as light passes unto your specimen, there will be an increased scattering of light. As that light passing unto your specimen is scattered, the transittance becomes slow = meaning you already formed a clot. Examples: Electra 750 and 750A FP910 Coag analyzer Coag-A-Mate X2XC Ortho Koagulab 165  Guard Interval Before your machine starts to measure the clotting time, it will not include the aspiration of the specimen and of the reagent. It will only start timing as soon as the reagent and specimen are totally mixed.  ADVANTAGES No interference from specimen MECHANICAL lipemia or bilirubinemia (icterus) CLOT END POINT DETECTION Ability to use specimen and reagent volumes as small as 25 !L in some instruments Able to detect weak clots  DISADVANTAGES MECHANICAL Reliance on the integrity of the CLOT END POINT entire coagulation cascade DETECTION Inability to observe graph of clot format  ADVANTAGES Good precision PHOTO- Increased test menu flexibility and specimen quality information when OPTICAL multiple wavelengths are used Ability to observe graph of clot formation with some instruments  DISADVANTAGES PHOTO- Interference from lipemia, hemolysis, bilirubinemia, and increased plasma OPTICAL proteins; this issue has been addressed by some manufacturers with readings from multiple wavelengths. May not detect short clotting times owing to long lag phase  VISUAL DETECTION ADVANTAGES DISADAVANTAGES Low cost Time consuming. Hands-on experience Lack of accuracy: provides valuable training temperature, pipetor, and understanding of the timing. clotting process. Less precise and reproducibility. Subjective Three Ways of Detecting Fibrin Clot Formation Visual Detection Electromechanical Detection Photo-Optical Detector  MANUAL VISUALIZATION OF CLOT - To detect if there is a clot, we tilt the tube and as you tilt it when you have observed a solid gel like formation that indicates that you have already formed a clot. - In secondary hemostasis, testing will always be after with the time. “Every second counts”  VISUAL DETECTION OF FIBRIN CLOT FORMATION BY STEININGER - this method, also known as the Tilt Tube Method. - variables that must be controlled include the temperature, pipet or calibration, and the accuracy of the timing devices. - it is difficult to control the temperature in this method because the tube is repeatedly removed from the water bath to tilt it and check for clot formation. Disadvantages: TEMPERATURE, PIPETOR, TIMING SUBJECTIVE TIME CONSUMING LESS PRECISE AND REPRODUCTIBILITY  ELECTROMECHANICAL DETECTION These instruments were based primarily on detection of the formation of a fibrin clot and replaced visual observation of the formation of a fibrin clot in a test tube. By the mid-1960s, electromechanical instruments were in widespread use. In the 1970s, photo-optical methods replaced electromechanical devices in most laboratories, except student laboratories or as a backup method in routine laboratories.  Advantages Disadvantages - fibrin is detected by 2 wire loops - Time interval in between clot detection is as electrode which is incorporated to at 0.5 seconds. Time interval or results will always have an increment of 0.5 an electromechanical instrument. - The increment in between clot - Sensitive to low fibrinogen levels detection is at 0.5 seconds. You will not be able to arrive with the actual timing. Being able to test even the smallest concentration of that analyte - Specimen carry over Sensitive even up to: