APTT HEMOSTASIS Insert

Transcription

1 APTT HEMOSTASIS Insert Ref.:502 Activated Partial Thromboplastin Time Intended use. System for determination of activated partial thromboplastin time (APTT) and measurement of coagulation factors based on activated partial thromboplastin time. Test principle. The reagent containing plasma activator (ellagic acid) triggers the intrinsic pathway of the coagulation cascade through the activation of factor XII (Hageman), which forms a complex with high molecular weight kininogen (HMWK) and prekallikrein (PK). The activated factor XII acts on factor XI, generating factor XIa, which, in presence of phospholipids and calcium, turns factor IX into an active enzyme (factor IXa). Factor IXa activates factor VIII, generating the IXaphospholipid-VIIIa complex, which activates factor X. The activated factor X turns prothrombin into thrombin, which acts on fibrinogen, generating fibrin. The formation of fibrin is macroscopically perceived by the formation of a coagulum. APTT is performed by incubating citrate plasma with the reagent containing activator and phospholipids. After adding calcium, the time to coagulation is measured. Summary. APTT Hemostasis contains substitutes for platelet phospholipids that, along with a soluble activator (ellagic acid), yield optimum conditions for activation via contact of coagulation factors (intrinsic pathway). Despite being sensitive to all coagulation factors deficiencies, except for factor VII, APTT Hemostasis detects secondary hemorrhagic disorders, mainly associated with deficiencies of factors VIII, IX, XI, XII, and prekallikrein. APTT Hemostasis can also be used to successfully monitor patients undergoing heparin therapy. The system is sensitive enough to differentiate distinct heparin concentrations, presenting prolonged time to coagulation that is proportional to the heparin concentration in plasma. Methodology. Reagents 1 - Reagent 1 - Store at 2-8 ºC. Reagent label bears expiration date. Ready to use. Contains ellagic acid 99 µ mol/l, rabbit brain phospholipid 0.007%, phenol 3 mmol/l, bovine albumin 0.005%, stabilizers, and preservative Coagulometry. Reagent 2 - Store at 2-30 ºC. Reagent label bears expiration date. Contains calcium chloride mmol/l, and sodium azide 0.095%. For in vitro diagnostic use. Disposal of all waste material should be in accordance with local guidelines. The usual security cares should be applied to the reagent handling. Reagent 2 contains sodium azide as preservative. Avoid ingestion. In case of contact with eyes, immediately flush eyes with plenty of water and get medical assistance. Sodium azide may react with lead and copper plumbing and yield highly explosive metal azides. On disposal, flush with a large volume of water to prevent azide accumulation. Storage and stability. Unopened reagents, when stored at indicated temperature, are stable up to the expiration date shown on the label. Reagent 1 should be out of refrigeration for only the time necessary to obtain the volume to be used in the test. Prolonged exposure to air may decrease Reagent 1 stability. The use of dirty pipet tips may also decrease Reagent 1 stability. Deterioration. reagent stability. Preanalytical influences. Microbial or chemical contamination may decrease APTT may be increased for people who use acetylsalicylic acid, aztreonam, ofloxacin, metronidazole, and phenytoin. APTT may be reduced for people who use antihistaminics, digitalis, oral contraceptives, tetracycline, and conjugated estrogens. It is also important to collect samples following the guideline below. Use plasma samples collected in anhydrous trisodium citrate 109 mmol/l (2%). Considering that the sample quality is fundamental to obtain accurate results, it is strongly recommended that you use the following procedure: Precautions and warnings Specimen collection and preparation Obtain blood through venous puncture, avoiding prolonged tourniquet application, hemolysis, bubbles, and aspiration of tissue fluid (factor III). The needle must penetrate the vein directly on the first attempt (atraumatic venous puncture). The blood must flow freely, without the need to use too much strength to pull the plunger. Do not use samples that were difficult to obtain (traumatic venous puncture). 01 Inglês - Ref.: 502

2 2. Collect the sample using plastic syringe and centrifuge it in plastic tubes. The use of non-siliconized glassware activates the coagulation factors and falsely reduces APTT. After removing the needle, use the central portion of the sample, using the first and last portions for other tests. If you are using vacuum blood collection systems, use plastic or siliconized glass tubes. When performing the collection for coagulation tests, draw two samples. Place the first sample in a tube without anticoagulant or in a tube containing citrate (blue cover), and discard it. The second sample must be placed in a tube containing citrate (blue cover) and it will be used for performing the tests. In case of multiple collections, the sample for coagulation tests must be obtained after the collection in tube without anticoagulant and before the collection in tube containing EDTA. 4. Mix 9 parts of blood with 1 part of citrate, or 3 ml of blood with 1 drop of Thrombstab (Labtest Ref. 45). Homogenize the tube 3 or 4 times by gentle inversion. Do not use oxalate, since factor V is very sensitive to this anticoagulant. 5. In patients who have hematocrit higher than 55%, the ratio blood volume/anticoagulant must be modified to ensure the accuracy of results. To calculate the volume of anticoagulant taking into account the hematocrit and blood volume, use the following equation: Anticoagulant Volume (ml) = x blood volume (ml) x (100 - hematocrit) Example. For a hematocrit of 60%, use 0.22 ml of citrate and complete the volume to 0 ml with blood. When using Thrombstab (Labtest Ref. 45), add 2 drops to 0.5 ml of water and use it in the ratio indicated by the calculation. 6. Centrifuge the sample in less than 1 hour after collection at 3000 rpm or 1500 g for 15 minutes. It is not necessary to remove the plasma from the tube. Keep the tube closed until test time to avoid changes in the sample ph, which may interfere in results. 7. Keep samples at 2-24ºCandperformtheAPTTtest up to 4 hours after collection. If fast freezing is a feasible option, plasma may be kept at - ºC for 2 weeks or - 70 ºC for 6 months. We recommend that samples be stored as 0.5mL aliquots to avoid sample evaporation during storage. Use adequate vials to store frozen samples ( cryotubes ). Samples must be rapidly thawed at 37 ºC and tested immediately. 8. Materials required not provided 2. The presence of coagula indicates that the sample must be rejected. Pipets to measure samples and reagent. Water bath kept at a constant temperature of 37 ºC. Timer. The following procedure refers to the manual technique. The reagent can be used for determining APTT in automated and semi-automated systems. Follow the instructions indicated by their vendors Perform the test in strictly clean glass tubes. The water bath temperature must be at ºC. Preheat Reagent 2 to 37 ºC. Incubate 0.1 ml of plasma (control or test) for at least 1 minute up to 10 minutes at 37 ºC. 5. Add 0.1 ml of Reagent 1, homogenize the tube and incubate it at 37 ºC for 3 to 5 minutes (activation time). To obtain reproducible results, the activation time must be standardized for all measurements. 6. Add 0.1 ml of Reagent 2 (previously heated to 37 ºC), starting the timer simultaneously. Mix the tube gently and place it in the water bath for 15 to seconds. 7. Manual procedure Get the tube, tilt it successively and observe the formation of a coagulum that prevents the liquid from moving. Stop the timer immediately and register the time. Internal quality control. The testing center must keep an internal quality control program that clearly defines all applicable regulations, objectives, procedures, and criteria for quality specifications and tolerance limits, corrective actions and registration of activities. materials should be used to assess imprecision and calibration deviations. It is recommended that you use the CLIA specifications for total error. Expected values. Each laboratory should evaluate the transferability of the expected values to its own patient population and, if necessary, estimate its own reference interval. Age 2 months 5 months Children above 6 months and adults Performance characteristics Method comparison. Interval (seconds) A group of 5 samples were assayed by the proposed method and a comparative product with similar method. The comparisons yielded a correlation coefficient of and the regression equation was y = x Using the regression equation, the total systematic error estimated is 76% for 26.7 seconds and 12% for 65.6 seconds. 02 Inglês - Ref.: 502

3 Imprecision - Within run Sample 1 Sample 2 Imprecision - Run-to-run Sample 1 Sample 2 N N 5 5 Mean Mean SD SD (%) CV (%) CV Factor VIII VIII IX IX XI XI XII XII Prekallikrein Factor Activity % APTT (seconds) > Total error. The total error (random error + systematic error) estimated is 13% for 26.7 seconds and 15% for 65.6 seconds. The results demonstrate that the product meets the CLIA specifications for total error ( 15%). Sensitivity to heparin. APTT is used to monitor heparin therapy, since the prolonging of the time to coagulation is directly proportional to the rise in heparin concentration. The anticoagulant action of heparin depends on several factors, such as adequate levels of antithrombin III, platelet activation and subsequent exposure of platelet factor 4. Medication, metabolic rate, heparin administration path, and time between blood collection and test performance interfere with the sensitivity test. The relative sensitivity of APTT Hemostasis for heparin can be determined with a sensitivity curve for heparin, which must be established by adding known amounts of heparin to a normal plasma pool and performing the APTT test. The testing center must use the same heparin as the one given to the patient, taking into account the variables that influence the test. The example below illustrates the relationship between heparin concentration and time to coagulation obtained with APTT Hemostasis, using a photo-optical coagulometer. Notes The material cleaning and drying are fundamental factors to the reagent stability and to obtain correct results. 2. The deionized or distilled water in the laboratory to prepare reagents, use in the measurements and for final glass washing must have resistivity 1 megaohm.cm, or conductivity 1 microsiems/cm and silicates concentration must be <0.1mg/L. It is suggested to consult to review physiopathological sources and drug interferences in results and methodologies. References International Committee for Standardization in Hematology. Thromb Haemostas 1976, 36: NCCLS. Collection, Transport, and Processing of Blood Specimens for Testing Plasma-Based Coagulation Assays; Approved Guideline Fourth Edition. NCCLS document H21-A4, 0 Heparin Concentration (units/ml) APTT (seconds) NCCLS. Procedures for the Collection of Diagnostic Blood Specimens by Venipuncture; Approved Standard Fifth Edition. NCCLS document H3-A5, 0 4. NCCLS. One-Stage Prothrombin Time (PT) Test and Activated Partial Thromboplastin Time (APTT) Test; Approved Guideline. NCCLS document H47-A, CLIA Requirements for Analytical Quality. Available at 6. Conway AM, Hinchliffe RF, Finn A, Bell F. Clin Lab Haem 1999, 21: Sensitivity to coagulation factors deficiency. Plasmas with moderate to severe deficiency of several factors were evaluated with APTT Hemostasis, which has shown an appropriate sensitivity to coagulation factors deficiency, according to the following table: 7. Flanders MM, Crist RA, Roberts WL, Rodgers GM. Clin Chem 05, 51: Jacobs DS, DeMott WR, Oxley DK. Laboratory Test Handbook, 5th edition, Lexi-Comp Inc., Hudson (Cleveland), 01: Labtest: data on file. 03 Inglês - Ref.: 502

4 Presentation Product APTT Hemostasis Reference 502-1/4 1 2 Contents 1X4mL 1X6mL Labtest Diagnóstica S.A. CNPJ: / Av. Paulo Ferreira da Costa, Vista Alegre - CEP Lagoa Santa. Minas Gerais Brasil - Consumer Service sac@labtest.com.br Application procedures using APTT Hemostasis are available for various automated instruments. Consumer information [Warranty conditions] Labtest Diagnóstica warrants the performance of this product under the specifications until the expiration date shown in the label provided that the procedures and storage conditions indicated on the label and in this insert have been followed correctly. Edition: February, 07 Ref.: Copyright by Labtest Diagnóstica S.A. Reproduction under previous autorization 04 Inglês - Ref.: 502

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6 Símbolos utilizados com produtos diagnósticos in vitro Símbolos usados con productos diagnósticos in vitro Symbols used with ivd devices Conteúdo suficiente para <n>testes Contenido suficiente para <n>tests Contains sufficient for <n>tests Risco biológico Riesgo biológico Biological risk Data limite de utilização (aaaa-mm-dd ou mm/aaaa) Estable hasta (aaaa-mm-dd o mm/aaaa) Use by (yyyy-mm-dd or mm/yyyy) Marca CE Marcado CE CE Mark Calibrator Material Tóxico Tóxico Poison Calibrator Material Reagente Reactivo Reagent Limite de temperatura (conservar a) Temperatura limite (conservar a) Temperature limitation (store at) Fabricado por Elaborado por Manufactured by Representante Autorizado na Comunidade Europeia Representante autorizado en la Comunidad Europea Authorized Representative in the European Community Número do lote Denominación de lote Batch code Consultar instruções de uso Consultar instrucciones de uso Consult instructions for use e Número do catálogo Número de catálogo Catalog Number e negativo negativo Negative control Adições ou alterações significativas Cambios o suplementos significativos Significant additions or changes e positivo positivo Positive control Produto diagnóstico in vitro Dispositivo de diagnóstico in vitro In vitro diagnostic device e Liofilizado Liofilizado Lyophilized Corrosivo Corrosivo Corrosive Ref.: Inglês - Ref.: 502