It is often, but not always, a phenomenon commonly caused by the anticoagulant EDTA. We report that EDTA and heparin can induce platelet clumping, and thus spuriously low platelet counts. This patient had an EDTA-dependent platelet agglutinin that caused in vitro platelet clumping, resulting in an artifactually low platelet count (ie, "pseudothrombocytopenia"). 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. Image 2. Individual platelets normally shrivel and disappear when exposed to the lysing reagents used to obtain automated WBC counts. The pathophysiology of pseudothrombocytopenia is not clearly defined, but it is suggested that an immune-mediated mechanism accounts for platelet clumping. EDTA-dependent pseudothrombocytopenia (EDTA-PTCP) is an in vitro phenomenon of platelet clumping that leads to spuriously low platelet counts by automatic hematology analyzers. When the number of platelets measured by the instrument is normal, the presence of platelet clumping is of little clinical significance. Platelet clumping can also occur in patients with antibodies that can bind to platelets and are activated by EDTA. Results from warmed EDTA tube (left) and Na Citrate tube (right). Image 1. We would emphasize that in the present study the phenomenon of platelet clumping took place 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 . The patient doesn't have thrombocytopenia. 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. Collect sample in pre-warmed EDTA tube and place in fresh hot pack or . Image 1. Four hours after the bolus, the platelet count from EDTA blood was 51 000/μL; at the same time, an automated platelet count from citrated blood was 215 000/μL. 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. 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 . Causes of platelet clumping include platelet activation (due to traumatic venipuncture) and EDTA-dependent antibodies that react with platelet glycoprotein IIb/IIIa. This behaviour may affect a sure identification of EDTA-dependent platelet clumping and may compromise the intra- and especially interlaboratory reproducibility of the results. Download Image Share Image Collection Instructions. If blood was exposed to EDTA for 10 to 15 minutes, the . This becomes very apparent when those meds are taken separately. Furthermore, true pseudothrombocytopenia was not confirmed in these animals. This behaviour may affect a sure identification of EDTA-dependent platelet clumping and may compromise the intra- and especially interlaboratory reproducibility of the results. References. Draw the specified amount of blood as per the package insert of the tube used. 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. Figure 3: Left peak in WBC histogram. Platelet satellitism as a cause of spurious thrombocytopenia. 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's sample has been drawn in sodium citrate, EDTA K2, sodium heparin, and warm saline replacements, and a true platelet count cannot be obtained. 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. (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. Conclusion: Platelets are adequate and estimated to be about 200,000/μL. 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 … EDTA-dependent pseudothrombocytopenia (EDTA-PTCP) is an in vitro phenomenon consisting of EDTA-induced platelet aggregation at room temperature ().This phenomenon occurs due to anti-platelet antibodies that cause platelet clumping in blood that had been . 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. Tags: EDTA, Platelet Aggregation, Platelet Clumping. EDTA is the anticoagulant of choice for a complete blood count (CBC) because of its ability to preserve blood cells. Pradella P, Bizzaro N, Potenza R, De Angelis V. IgG platelet . Figure 1). Ordering Instructions. (1) 16 level 1 Tigerwraith If the platelet count is less than 20,000/ccm, submit 7-10 mL of whole blood. So, why can't we just order one of these other tubes and start reporting results? 11643. Pseudothrombocytopenia is a condition in which individuals with preexisting antibodies have platelet clumping when blood is drawn into an Ethylenediaminetetraacetic acid (EDTA)-containing tube. Ethylenediaminetetraacetic acid (EDTA) is commonly used as an anticoagulant in sampling tubes for blood cell counts. Does this seem accurate? EDTA lavender-top tube or microcollection tube. 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. Several remedies have been proposed, such . Platelet aggregation (clumping) will affect platelet counts. In the latter case, the clumping can be corrected by using blood collection tubes containing an alternative anticoagulant, such as sodium citrate. 7 mL whole blood collected in an EDTA (lavender-top) tube. Test Name Alias. To obtain reliable platelet counts in such cases, laboratorians often collect and analyze a citrated or nonanticoagulated blood specimen. SPECIMEN PROCESSING: . 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. It was when he had ET instead of CMML and his platelets were normally over a million. 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. Introduction. Normal platelet count with no clumping seen with Na Citrate. Lori C. Member. Our retrospective review underscores the importance of recognizing the principle of Pseudothrombocytopenia due to EDTA-induced Platelet Satellitism. 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. Bali05. In rare situations, an EDTA-dependent pseudothrombocytopenia can occur. In the latter case, the clumping can be corrected by using blood collection tubes containing an alternative anticoagulant, such as sodium citrate. ACD is pretty good as an anticoagulant, although - the same as for 3.2% citrate . When this occurs the platelet count will be removed from the FBC . Platelet Clumping or Aggregation. 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. it has also been observed in disease-free patients. Clumping of platelets in blood anticoagulated with EDTA is a main cause of reports of falsely low platelet counts by automated analyzers. 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. 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. Platelet Count on Citrate Tube. WBC histogram showed a left peak (Figure 3). Platelet satellitism and platelet clumping can cause pseudo-thrombocytopenia. Invert tubes 8-10 times, do not shake as it may cause foaming or hemolysis. Platelet Count (Citrate/Blue Tube) is for platelet clumping due to EDTA. Hence, we considered that this low platelet count was due to EDTA-PTCP. It is a rare condition that occurs when an IgG antibody forms in the presence of EDTA, the anticoagulant that is used for the collection of hematology blood specimens. Diagnosis and discussion. EDTA leads to platelet shinkage and was once widely reported as the cause of the so called pseudothrombocytopenia. 2. Oxalate and heparin are too occasionally reported to induce platelet clumping. Quantitative platelet disorders have varied etiology. If multiple draw, collect EDTA (lavender-top) tube last. The clumping disappears when an anticoagulant other than EDTA is used. 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. 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. H. HNISHA Networker. (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. All other CBC parameters are reported from the EDTA tube. Platelets clump in all tubes, and multiple platelet clumps are observed under the microscope. Insufficient, delayed, or inadequate mixing may result in platelet clumping, clotting, and/or incorrect test results. (10) Commonly, this clumping is caused by an alteration of the platelet surface glycoproteins when they are incubated with a calcium . Heparin causes clumping of platelets and is not recommended. 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. Perform a platelet count at time 0. Published studies have shown that several other alternate methods have been helpful in resolving platelet clumping issues. 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 . 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 . So, now they draw Grant's blood using sodium citrate. A peripheral blood film from EDTA blood (Figure 2) showed marked platelet clumping, which was not present on a film from citrated blood. These antibodies can react with certain receptors present on the platelet causing clamping. The Epic . Repeat the platelet count. Similarly, the numbers of platelets cannot be accurately counted manually (with a hemocytometer) in clumped samples (it is impossible . Another reason can be presence of EDTA dependent antibodies in the blood. (yellow-top) tubes will no longer be accepted because of the high incidence of platelet clumping associated with this anticoagulant. Platelet Count (Citrate Tube) | Plt Count (Citrate Tube) | 8147. Platelet satellitism was first reported in the early 1960s. Norman, EJ, Barron, RC, Nash, AS, Clampitt, RB. Both increases and decreases in the platelet count can point to abnormal conditions of excess bleeding or clotting. The antibodies are IgG (33-50% of the cases), IgM (10-63%), or IgA (4-40%) 12-15. Refrigeration can precipitate fibrin and trap WBC and platelets. The clumping disappears when an anticoagulant other than EDTA is used. Traumatic draw can introduce thromboplastin and trap WBC and platelets. 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. 1 mL whole blood EDTA (lavender-top) tube. The decline in the platelet . The abciximab infusion was stopped. For EDTA platelet clumping ONLY, draw an additional blue-top sodium citrate tube. These bleeding or clotting disorders or bone marrow diseases require the . 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. 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). Tube must be full. Platelet . For the resolution of spurious thrombocytopenia due to platelet clumping in EDTA. 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 histogram revealed saw-tooth appearance (Figure 4). The platelet count was higher in all CTAD-supplemented tubes except one, . EDTA leads to platelet shinkage and was once widely reported as the cause of the so called pseudothrombocytopenia. In order to continue our current process, I am in the midst of doing a correlation between EDTA platelet counts vs. citrated counts. . Laboratory data. Messages 77 Best answers 0. The result is a low platelet count that is . ( Bobba RK, Doll DC. . 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. Figure 2: Peripheral smear in an EDTA sample with platelet clumping. The method of screening for platelet clumping with the help of XE5000 images is convenient. The most common cause of this phenomenon is platelet clumping. This test may be ordered when platelets show clumping in EDTA anticoagulant. The Thromboexact specimen is used when a patient has EDTA mediated platelet clumping and a true platelet count can not be obtained. For patients with suspected EDTA platelet clumping, the EDTA and Sodium Citrate specimens should be drawn together. Transport Container. Platelet clumping is not always corrected . This entity is in vitro phenomena which has no clinical bearing in terms of a predisposition to increased mucous membrane bleeding. Thread starter amyhawk; Start date Jul 28, 2010; A. amyhawk New. The MPV from the citrate tube is also reported, but no correction factor is applied because the MPV is not affected by dilution. Platelet changes. platelets were seen in peripheral smear (Figure 2). 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 . Interface Order Alias. 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. Jul 28, 2010 #1 Does anyone have a diagnosis code for pseudothrombocytopenia due to EDTA platelet clumping? For patients with suspected cold agglutinins, pre-warm all collection materials using a hot pack or heel warmer. Clumped platelets seen with EDTA. 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. cases, clumping of the platelets occurs well after blood collection. We would emphasize that in the present study the phenomenon of platelet clumping took place (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. 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) 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). Pseudothrombocytopenia due to platelet clumping in EDTA This peripheral blood smear shows platelet clumping (arrows) in an EDTA-anticoagulated blood sample. Causes of platelet clumping include platelet activation (due to traumatic venipuncture) and EDTA-dependent antibodies that react with platelet glycoprotein IIb/IIIa. These antiplatelet antibodies, usually IgG or IgM, and rarely IgA, recognize platelet antigens on the platelet membrane modified by EDTA 1, 3, 4, 7). Platelet Count: Minimum Volume: 2 mL : 20,000-45,000 : 5 . For the specific diagnosis of EDTA-induced thrombocytopenia, follow these steps: Collect the blood specimen in an EDTA-containing tube. Because the EDTA-PTCP condition indicates a tendency for platelet clumping upon in vitro exposure to EDTA. Do not refrigerate. Diagnostic Use and Interpretation. The analyser gives a falsely decreased platelet count with an EDTA sample. Whole blood should be collected venous in EDTA-2K or EDTA-3K anticoagulant. 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. In this article, a 10-year-old boy with EDTA- and heparin-dependent PTCP is presented because of rare presentation. . April 3, 2008 at 5:43 pm #20425. EDTA is the anticoagulant of choice for a complete blood count (CBC) because of its ability to preserve blood cells. It is often, but not always, a phenomenon commonly caused by the anticoagulant EDTA. Platelet clumping is a common laboratory phenomenon that complicates or precludes reporting of platelet count. ACD is pretty good as an anticoagulant, although - the same as for 3.2% citrate . As in other literature cases, a clear correlation between the . EDTA whole blood smear had many platelet clumps noted (EDTA induced thrombocytopenia). 5, 6 misdiagnosis of ptcp … This often results in a falsely decreased count as clumps of platelets will not be counted with any automated hematology analyzers. In many cases the EDTA in a lavender top tube causes the platelet clumping which does not occur in a blue top (citrate tube). (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. Platelet clumping is a common laboratory phenomenon that complicates or precludes reporting of platelet count. Maintain specimen at room temperature. Jul 29, 2010 #2 1. Also, what causes platelet clumping? Turnaround Time: Between 45 minutes and 2 hours. 60 View 1 excerpt, references background Ethylenediaminetetraacetic acid-dependent pseudothrombocytopenia in a cardiac surgical patient. It is often, but not always, a phenomenon commonly caused by the anticoagulant EDTA. We got a platelet count back at like 300,000 and knew something was up. These include drawing specimens in CTAD, ACD, or 'ThromboExact' 1 tubes, or adding amikacin or kanamycin to the EDTA after the specimen is drawn. EDTA platelet clumping. Platelet aggregation score was >2 in 11/46 EDTA tubes and only in one EDTA + CTAD specimen. In the latter case, the clumping can be corrected by using blood collection tubes containing an alternative anticoagulant, such as sodium citrate. Addition of CTAD to EDTA when sampling feline blood is a useful option to reduce platelet clumping. 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 . 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. 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. Selection of Auxiliary Reagents to EDTA. Pseudothrombocytopenia is defined as a falsely low platelet count, with an estimated frequency of between 1 in 1,000 and 1 in 10,000 . 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. EDTA-dependent pseudothrombocytopenia (EDTA-PTCP) is a common laboratory phenomenon. Platelet Clumping or Aggregation. 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. Messages 5 Best answers 0. 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. Causes of platelet clumping include platelet activation (due to traumatic venipuncture) and EDTA-dependent antibodies that react with platelet glycoprotein IIb/IIIa. Platelets are often clumped on smears obtained from capillary blood, contributing to imprecision. Jack, Grant has had EDTA platelet clumping before. Platelet clumping is a common laboratory phenomenon that complicates or precludes reporting of platelet count. The Sodium Citrate is now stable for 24 hours. 4, 5 although other anticoagulants such as heparin and sodium citrate rarely induce such a phenomena, it is possible. 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 . February 2017—I have an oncology patient with a diagnosis of immune thrombocytopenia. Figure 1. Minimum Volume. 1.
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