In the presence of EDTA in vitro, cryptic epitopes of the glycoprotein IIb/IIIa complex on the platelet membrane suffer a conformational change and are exposed to acquired or naturally . EDTA-dependent PTCP is the phenomenon of a spurious low platelet count due to the appearance of antiplatelet autoantibodies that cause platelet clumping in blood anticoagulated with EDTA 5, 6). Platelet Clumping or Aggregation. Platelet Abnormalities and Conditions: Pseudothrombocytopenia is a problem with the sample in-vitro (in the test tube) that is causing a falsely low platelet count. Several remedies have been proposed, such . On theoretical grounds (backed by some empirical facts), and since EDTA is a primary ingredient of the AZ vaccine, this, in turn, suggests that the injection of the AZ vaccine in vivo runs the risk of creating blood clots. We got a platelet count back at like 300,000 and knew something was up. Pseudothrombocytopenia due to platelet clumping in EDTA This peripheral blood smear shows platelet clumping (arrows) in an EDTA-anticoagulated blood sample. Figure 2: Peripheral smear in an EDTA sample with platelet clumping. 1. Laboratory data. So, now they draw Grant's blood using sodium citrate. Platelets are often clumped on smears obtained from capillary blood, contributing to imprecision. EDTA platelet clumping. Because the EDTA-PTCP condition indicates a tendency for platelet clumping upon in vitro exposure to EDTA. This behaviour may affect a sure identification of EDTA-dependent platelet clumping and may compromise the intra- and especially interlaboratory reproducibility of the results. April 3, 2008 at 5:43 pm #20425. Download Image Share Image Conclusion: Platelets are adequate and estimated to be about 200,000/μL. The antibodies are IgG (33-50% of the cases), IgM (10-63%), or IgA (4-40%) 12-15. Interface Order Alias. Messages 77 Best answers 0. Platelet histogram revealed saw-tooth appearance (Figure 4). I'm obviously not pleased about having low (and maybe falling) platelets, but three CBC's in seven days all coming back with unreadable numbers is . For patients who repeatedly have platelet clumps which preclude determination of an accurate platelet count, it is now possible to order a platelet count from a citrate tube. (yellow-top) tubes will no longer be accepted because of the high incidence of platelet clumping associated with this anticoagulant. The Epic . Diagnosis and discussion. This test may be ordered when platelets show clumping in EDTA anticoagulant. The clumping disappears when an anticoagulant other than EDTA is used. Platelet Count: Minimum Volume: 2 mL : 20,000-45,000 : 5 . Also, what causes platelet clumping? We would emphasize that in the present study the phenomenon of platelet clumping took place The patients do not have any signs and symptoms of bleeding, since this is a laboratory artifact and not an in vivo decrease in platelet count. 5, 6 misdiagnosis of ptcp … Its prevalence is reported to vary between 0.1-2% among hospitalized patients [1-3] and 15-17% in outpatients evaluated for isolated thrombocytopenia [4, 5].In contrast to serious and potential life-threatening causes of thrombocytopenia [], EDTA-PTCP is solely an in vitro effect without any clinical . Pseudothrombocytopenia is an in vitro phenomenon that can be transient or persistent, and platelet clumping is most often due to antibodies directed against epitopes on the platelets. This article discusses the mechanism briefly: The term pseudothrombocytopenia is used to define a state with a falsely low platelet count reported by automated hematology analyzers due to platelet clumping. Platelet aggregation score was >2 in 11/46 EDTA tubes and only in one EDTA + CTAD specimen. Lori C. Member. This is due to EDTA-induced exposure of platelet antigens, which causes clumping in patients with antibodies (which can be naturally occurring) to these antigens. These include drawing specimens in CTAD, ACD, or 'ThromboExact' 1 tubes, or adding amikacin or kanamycin to the EDTA after the specimen is drawn. The abciximab infusion was stopped. EDTA-dependent pseudothrombocytopenia (EDTA-PTCP) is a common laboratory phenomenon. Messages 5 Best answers 0. 8 years ago by Dr.AG 0. the clump of platelets on peripheral blood smear are usually duo to poorly anticoagulated blood or In vitro artifact caused by EDTA or cold and leads to false low platelet count. Image 1. These antibodies can react with certain receptors present on the platelet causing clamping. Jack, Grant has had EDTA platelet clumping before. Thread starter amyhawk; Start date Jul 28, 2010; A. amyhawk New. Platelets clump in all tubes, and multiple platelet clumps are observed under the microscope. Novel method to dissociate platelet clumps in EDTA-dependent pseudothrombocytopenia based on the pathophysiological mechanism Abstract Background: EDTA-dependent pseudothrombocytopenia (EDTA-PTCP) is an in vitro phenomenon of platelet clumping that leads to spuriously low platelet counts by automatic hematology analyzers. We would emphasize that in the present study the phenomenon of platelet clumping took place Image 2. Similarly, the numbers of platelets cannot be accurately counted manually (with a hemocytometer) in clumped samples (it is impossible . The three different scenarios in which pseudothrombocytopenia can be seen are EDTA-induced platelet clumping, platelet satellitism, and giant platelet syndromes.3-5 in all three; the platelet count is falsely low because giant platelets and aggregates are not counted by the electronic particle counter. It is often, but not always, a phenomenon commonly caused by the anticoagulant EDTA. Perform a platelet count at time 0. Transport Container. Other Comments: A Citrated Platelet Count will be suggested by Haematology when clumped platelets have been seen on a blood film on one or more occasions, significantly lowering the platelet count. Clumping of platelets in blood anticoagulated with EDTA is a main cause of reports of falsely low platelet counts by automated analyzers. Jul 28, 2010 #1 Does anyone have a diagnosis code for pseudothrombocytopenia due to EDTA platelet clumping? I have found there to be a 20-25% difference between the two values, the citrated platelet count being lower even after the 1.1 multiplication factor. It is often, but not always, a phenomenon commonly caused by the anticoagulant EDTA. EDTA leads to platelet shinkage and was once widely reported as the cause of the so called pseudothrombocytopenia. Clumped platelets seen with EDTA. For patients with suspected cold agglutinins, pre-warm all collection materials using a hot pack or heel warmer. As in other literature cases, a clear correlation between the . These bleeding or clotting disorders or bone marrow diseases require the . The Thromboexact specimen is used when a patient has EDTA mediated platelet clumping and a true platelet count can not be obtained. Conclusions: Prewarming EDTA blood samples to 37°C prior to hematologic analysis increased platelet counts overall in canine, feline, and equine blood, but did not abrogate platelet clumping and pseudothrombocytopenia fully in some cases. Collect sample in pre-warmed EDTA tube and place in fresh hot pack or . We report that EDTA and heparin can induce platelet clumping, and thus spuriously low platelet counts. Pseudothrombocytopenia is a condition in which individuals with preexisting antibodies have platelet clumping when blood is drawn into an Ethylenediaminetetraacetic acid (EDTA)-containing tube. In rare situations, an EDTA-dependent pseudothrombocytopenia can occur. 2. Platelet changes. When this occurs the platelet count will be removed from the FBC . Hence, we considered that this low platelet count was due to EDTA-PTCP. (3) These modified platelet antigens then react to anti-platelet autoantibodies (Immunoglobulins of both the IgG and IgM types (2)) to form these large agglutinates. 2, 3 platelet clumping in the presence of edta is caused by an autoantibody against glycoprotein iib/iiia located on the cell membrane of platelets. The clumping disappears when an anticoagulant other than EDTA is used. Whole blood should be collected venous in EDTA-2K or EDTA-3K anticoagulant. EDTA whole blood smear had many platelet clumps noted (EDTA induced thrombocytopenia). Heparin causes clumping of platelets and is not recommended. . Platelet Count (Citrate/Blue Tube) is for platelet clumping due to EDTA. If multiple draw, collect EDTA (lavender-top) tube last. Another reason can be presence of EDTA dependent antibodies in the blood. INF typically causes thrombocytopenia (decline of platelet count ) Ribavirin typically causes thrombocytosis (increase of platelets) My guess is one suppresses platelet production and the other stimulates it. 1 mL whole blood EDTA (lavender-top) tube. When blood was processed within 5 minutes of phlebotomy, the percent of platelets activated in response to ADP was greater with citrate than with EDTA (activation of platelets in response to 0.8 μmol/L ADP for platelets in citrate was 40±6%; for platelets in EDTA, 26±5%, Fig 2). In the latter case, the clumping can be corrected by using blood collection tubes containing an alternative anticoagulant, such as sodium citrate. 60 View 1 excerpt, references background Ethylenediaminetetraacetic acid-dependent pseudothrombocytopenia in a cardiac surgical patient. platelets were seen in peripheral smear (Figure 2). Does this seem accurate? When the number of platelets measured by the instrument is normal, the presence of platelet clumping is of little clinical significance. (10) Commonly, this clumping is caused by an alteration of the platelet surface glycoproteins when they are incubated with a calcium chelator such as EDTA. Invert tubes 8-10 times, do not shake as it may cause foaming or hemolysis. For patients with suspected EDTA platelet clumping, the EDTA and Sodium Citrate specimens should be drawn together. Tube must be full. Results from warmed EDTA tube (left) and Na Citrate tube (right). Platelet satellitism as a cause of spurious thrombocytopenia. Traumatic draw can introduce thromboplastin and trap WBC and platelets. edta-dependent pseudothrombocytopenia is a rare phenomenon (i.e., around 0.1% in the general population), which is mostly due to the presence of edta-dependent antiplatelet antibodies that react optimally between 0°c and 4°c, recognize the cytoadhesive receptors gpiib-iiia, stimulate the expression of activation antigens, trigger activation of … February 2017—I have an oncology patient with a diagnosis of immune thrombocytopenia. Ethylenediaminetetraacetic acid (EDTA) is commonly used as an anticoagulant in sampling tubes for blood cell counts. If a platelet count is still required in such cases, a manual platelet count is done using finger-prick blood and directly collecting the blood into . The method of screening for platelet clumping with the help of XE5000 images is convenient. If platelet clumps are still present in the EDTA tube, the platelet count and white blood cell count from the citrate tube are multiplied by 1.1 and reported. WBC histogram showed a left peak (Figure 3). This is a phenomenon that occurs when the anticoagulant in the lavender-top tube (K2EDTA) causes the platelets to clump , leading to a falsely low platelet count. Figure 3: Left peak in WBC histogram. EDTA is the anticoagulant of choice for a complete blood count (CBC) because of its ability to preserve blood cells. Refrigeration can precipitate fibrin and trap WBC and platelets. Furthermore, true pseudothrombocytopenia was not confirmed in these animals. If the platelet count is less than 20,000/ccm, submit 7-10 mL of whole blood. Introduction. In the latter case, the clumping can be corrected by using blood collection tubes containing an alternative anticoagulant, such as sodium citrate. EDTA is the anticoagulant of choice for a complete blood count (CBC) because of its ability to preserve blood cells. The MPV from the citrate tube is also reported, but no correction factor is applied because the MPV is not affected by dilution. This patient had an EDTA-dependent platelet agglutinin that caused in vitro platelet clumping, resulting in an artifactually low platelet count (ie, "pseudothrombocytopenia"). SPECIMEN PROCESSING: . However, aggregation of platelets was not detected in blood samples with sodium citrate, and platelet count was normal. By using the Thromboexact tube a true platelet count . Platelet clumping can also occur in patients with antibodies that can bind to platelets and are activated by EDTA. Platelet . In many cases the EDTA in a lavender top tube causes the platelet clumping which does not occur in a blue top (citrate tube). EDTA lavender-top tube or microcollection tube. The platelet count was higher in all CTAD-supplemented tubes except one, . To test the effects of different auxiliary reagents on K 2-EDTA-treated blood samples, 10 mg of amikacin, 13 mg of aminophylline, 0.5 mg of vitamin B 6, and 8,000 IU of gentamicin was added to the K 2-EDTA-treated blood samples.The results showed that the platelet count of the amikacin-treated blood sample remained unchanged for up to 4 hours after . Both increases and decreases in the platelet count can point to abnormal conditions of excess bleeding or clotting. Figure 1. Image 1. Platelet clumping can happen if there was a traumatic venipuncture, that is collection of the blood from the vein caused platelet activation that led to clumping of the platelets. We use two criteria to screen for platelet aggregation: (1) an abnormal platelet count in EDTA‐treated blood from a patient lacking clinical signs of a platelet disorder, and (2) an instrument flag for platelet clumps. This often results in a falsely decreased count as clumps of platelets will not be counted with any automated hematology analyzers. Minimum Volume. ( Bobba RK, Doll DC. Herein, we discuss a case of a 14-year-old girl who was found to have platelet clumping and discuss the work-up she underwent to investigate her . The patient's sample has been drawn in sodium citrate, EDTA K2, sodium heparin, and warm saline replacements, and a true platelet count cannot be obtained. To obtain reliable platelet counts in such cases, laboratorians often collect and analyze a citrated or nonanticoagulated blood specimen. Platelet clumping is a common laboratory phenomenon that complicates or precludes reporting of platelet count. For the specific diagnosis of EDTA-induced thrombocytopenia, follow these steps: Collect the blood specimen in an EDTA-containing tube. Platelet aggregation (clumping) will affect platelet counts. Platelet clumping is not always corrected . Platelet Count (Citrate Tube) | Plt Count (Citrate Tube) | 8147. Insufficient, delayed, or inadequate mixing may result in platelet clumping, clotting, and/or incorrect test results. 1. 1, 2 However, there have been incidents of falsely low platelet counts with various hematology analyzers because of platelet clumping when EDTA is used as the anticoagulant for blood collection. Platelet clumps tend to form in samples collected with difficulty and in a small number of individuals (about 1/2000) whose platelets react with the EDTA anticoagulant in lavender-top tubes. Several methods such as vortex mixing, changing anticoagulant to sodium citrate or heparin, and adding amikacin to ethylenediaminetetraacetic acid (EDTA) have been routinely used for managing pseudothrombocytopenia. (3) These modified platelet antigens then react to anti-platelet autoantibodies (Immunoglobulins of both the IgG and IgM types (2)) to form these large agglutinates. EDTA leads to platelet shinkage and was once widely reported as the cause of the so called pseudothrombocytopenia. Turnaround Time: Between 45 minutes and 2 hours. Jul 29, 2010 #2 This entity is in vitro phenomena which has no clinical bearing in terms of a predisposition to increased mucous membrane bleeding. 4, 5 although other anticoagulants such as heparin and sodium citrate rarely induce such a phenomena, it is possible. It is often, but not always, a phenomenon commonly caused by the anticoagulant EDTA. Maintain specimen at room temperature. All other CBC parameters are reported from the EDTA tube. Platelet satellitism was first reported in the early 1960s. 1, 2 However, there have been incidents of falsely low platelet counts with various hematology analyzers because of platelet clumping when EDTA is used as the anticoagulant for blood collection. The most common cause of this phenomenon is platelet clumping. (1) 16 level 1 Tigerwraith 11643. Platelet clumping in EDTA-anticoagulated blood occurs in vitro when the samples of some subjects are analyzed at room temperature, but not at 37°C.1,2 This well-recognized phenomenon is caused by natural antiplatelet autoantibodies,3 and is responsible for spurious low platelet counts (pseudothrombocytopenia) when samples are analyzed by automatic instruments.4 On the other hand, erythrocyte . cases, clumping of the platelets occurs well after blood collection. Published studies have shown that several other alternate methods have been helpful in resolving platelet clumping issues. References. Sometimes, changing the anticoagulant in which the blood is collected from EDTA to citrate or heparin may solve the problem but rarely, platelets may clump on being exposed to any anticoagulant. In this article, a 10-year-old boy with EDTA- and heparin-dependent PTCP is presented because of rare presentation. Addition of CTAD to EDTA when sampling feline blood is a useful option to reduce platelet clumping. All I can find on the web is stories about Pseudothrombocytopenia or platelet clumping - basically a sample processing issue (i.e., I don't see medical literature on clumping with thrombocytopenia). Pradella P, Bizzaro N, Potenza R, De Angelis V. IgG platelet . The pathophysiology of pseudothrombocytopenia is not clearly defined, but it is suggested that an immune-mediated mechanism accounts for platelet clumping. It was when he had ET instead of CMML and his platelets were normally over a million. Normal platelet count with no clumping seen with Na Citrate. Quantitative platelet disorders have varied etiology. This becomes very apparent when those meds are taken separately. Platelet Count on Citrate Tube. Draw the specified amount of blood as per the package insert of the tube used. ACD is pretty good as an anticoagulant, although - the same as for 3.2% citrate . A small whole blood clot or very small fibrin clots in the EDTA anticoagulated specimen will usually be associated with clumping of platelets on the slide, and with a false low platelet count. Repeat the platelet count. For the resolution of spurious thrombocytopenia due to platelet clumping in EDTA. These antiplatelet antibodies, usually IgG or IgM, and rarely IgA, recognize platelet antigens on the platelet membrane modified by EDTA 1, 3, 4, 7). In order to continue our current process, I am in the midst of doing a correlation between EDTA platelet counts vs. citrated counts. Diagnostic Use and Interpretation. For EDTA platelet clumping ONLY, draw an additional blue-top sodium citrate tube. In vitro platelet clumping caused by ethylenediaminetetraacetic acid (EDTA)-dependent agglutinins (naturally occurring antibodies) In vitro platelet clumping caused by an insufficiently anticoagulated specimen: In vitro platelet clumping caused by glycoprotein IIb/IIIa inhibitors (eg, abciximab) (NOTE: these can also cause true thrombocytopenia) Figure 1). Platelet satellitosis and clumping is an in vitro phenomenon most often seen in blood films made from EDTA tubes, perhaps caused by EDTA-mediated IgG autoantibodies directed against the platelet glycoprotein IIb/IIIa complex and the neutrophil Fc γ receptor. The patient doesn't have thrombocytopenia. This behaviour may affect a sure identification of EDTA-dependent platelet clumping and may compromise the intra- and especially interlaboratory reproducibility of the results. Platelet satellitism and platelet clumping can cause pseudo-thrombocytopenia. So, why can't we just order one of these other tubes and start reporting results? (10) Commonly, this clumping is caused by an alteration of the platelet surface glycoproteins when they are incubated with a calcium . Do not refrigerate. Test Name Alias. Selection of Auxiliary Reagents to EDTA. In vitro platelet clumping in the presence of EDTA is a rare, but misleading phenomenon, the recognition of which is important in order to avoid expensive and potentially harmful procedures. The Sodium Citrate is now stable for 24 hours. (10) Commonly, this clumping is caused by an alteration of the platelet surface glycoproteins when they are incubated with a calcium chelator such as EDTA. A peripheral blood film from EDTA blood (Figure 2) showed marked platelet clumping, which was not present on a film from citrated blood. Bali05. In the latter case, the clumping can be corrected by using blood collection tubes containing an alternative anticoagulant, such as sodium citrate. If blood was exposed to EDTA for 10 to 15 minutes, the .
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