EDTAK3抗凝剂导致血小板假性减少1例报道[转帖]

EDTAK3抗凝剂导致血小板假性减少1例报道 北京协和医院检验科 张时民 　　EDTAK3作为血常规检测的抗凝剂已被公认并得到广泛使用。但EDTAK3导致血小板发生聚集，并在血细胞计数仪测定中被视为非血小板而不被计数，导致血小板假性减少（Pseudothrombocytopenia, PTCP）的事偶有发生，国外曾有多例报道，国内未见类似报道，应当引起重视。 　　1、病例介绍和相关实验检查 　　患者男，43岁，因发热到医院就诊，做血常规检查红细胞和白细胞及相关参数正常，但血小板仅为14×109/L，复查后血小板依然较低，被急收入院检查治疗。患者无明显出血倾向，无鼻出血、齿龈出血、血尿、皮肤紫癜、头痛、腹痛、肝肾疾病等问题。多次复查血小板在10～30×109/L之间，初步疑为药物原因或免疫性疾病导致血小板减少，原因待查。住院期间进行骨髓检查，提示骨髓增生活跃，粒系、红系、淋巴细胞比例形态正常，巨核细胞3个，血小板数量不少。其他化验检查正常，但血清IgG18.7～18.9g/L；IgA4.46～5.36g/L；血小板抗体 PAIgG 476～581ng/107PLT，明显高于正常参考范围。 　　患者住院期间进行血常规化验全部采用美国BD公司生产EDTAK3抗凝管抽取静脉血，在ADVIA 120及MEK-6108型血液分析仪上测定，前者为采用激光技术和组化染色原理的五分类血细胞分析仪，后者为普通电阻式三分类血细胞分析仪，全部采用仪器原装配套试剂，并每日质控合格。 　　对患者的EDTAK3抗凝血进行涂片检查中发现，该患者血片中有大量聚集的血小板出现，一般以30～50个血小板聚集在一起为多见，其血小板聚集体比正常白细胞大2-5倍（图1-6），将该血样置于许汝和氏稀释液中，在计算盘上计数，同样发现多达50个以上的血小板密集聚在一起，其大小相当于白细胞的3～5倍，无法计数。而将患者的末梢血液直接稀释于许汝和氏稀释液中，经显微镜下计数得到血小板数为288×109/L，与EDTAK3抗凝血结果相差10倍以上，其血片观察，血小板数量正常、散在、无聚集现象。将不抗凝的末梢血直接予稀释液后，在SYSMEX KX-21等细胞计数仪上测定，血小板计数结果多在215～292×109/L之间，血小板数量正常。 　　2、讨论 　　EDTAK3做为抗凝剂，使得血液不凝固并保持红细胞、白细胞、血小板体积形态不发生改变，从而进行血细胞计数和分析，已被广泛应用并被作为标准执行。但是EDTAK3做为抗凝剂又确有促使或诱导导致血小板发生凝集，从而导致血小板计数假性低下的问题也偶有出现。在《诊断学》教科书上及国外出版的血液学检验书籍中都有简要说明，国外的有关文献报道也很多，而在国内检验书籍中和文献中却很少提到，值得引起检验界同行的重视。 　　EDTAK3导致在血细胞分析仪上血小板计数假性减少的主要原因为血小板发生了聚集。大量成堆的血小板聚在一起，超过了血小板计数阈值设定的范围，也超过了红细胞、白细胞的阈值设定范围，因此它即不被认做血小板，也不被红细胞和白细胞计数区域认定，甚至在直方图上都得不到显示和提示（图7、8），但在淋巴细胞、单核细胞、和大的不成熟细胞区出现较多信号，在粒细胞区域上方出现一排表示大细胞的、横向密集的散点。在三分类式血球分类直方图上也没有出现异常图形（图9）。 　　EDTAK3导致发生血小板聚集的原因可能与一种抗血小板抗体的自身抗体有关，或血小板膜表面存在的某些隐匿性抗原有关。此类患者经化验检查，常有免疫球蛋白增高、抗血小板抗体增高等问题。这些病例多出现在实体瘤、髓或淋巴系统增生症、自身免疫病、心脏疾病、干燥综合征、浓毒血症、肝硬化以及一些不明原因疾病和某些查体者身上。有关EDTAK3导致血小板假性降低的报道，这些病例提到的患者均无出血性疾病、血液病和导致血小板减少的疾病。报道中均发现经EDTAK3抗凝处理的血液，出现血小板减少问题，一般通过血片观察发现血小板大量聚集的信息，然后采用如枸掾酸盐、草酸盐、肝素钠、ACD液等方式抗凝血液，采用计数板方法或血球计数仪测定得到正确血小板计数结果。 　　国外使用自动血液分析仪和EDTAK3抗凝静脉血做血常规检查历史比我们长，因此发现这种问题较多、较早，发现问题和经验都较多。我国近几年才逐步推广采用静脉血做血常规检查，其中的一些问题还未注意到。例如此类问题，应该按照有关血液常规检查的基本要求，对红细胞、白细胞、血小板任何一项数值或直方图出现异常或有异常提示的标本实行推片检查，可避免此类问题发生。 [upload=jpg]https://www.yeec.com/uploadimages1/forum/jyxg/20021042230398751.jpg[/upload] 参考文献： 1.戚仁铎主编：《诊断学》第四版，人民卫生出版社，P351， 2.John.V. Dacie and S.M. Lewis: Practical Heamatology,6th edition, P82 3.Christopoulos CG,Machin SJ. A new type of pseudothrombocytopenia:EDTA-mediated agglutination of platelets bearing Fab fragments of a chimaeric antibody. Br J Haematol 1994,87(3),650-652 4. Bizzaro N, Brandalise M. EDTA-dependent pseudothrombocytopenia. Association with antiplatelet and antiphospholipid antibodies. Am J Clin Pathol 1995 ;103(1):103-107 5. Wilkes NJ, Smith NA, Mallett SV. Anticoagulant-induced pseudothrombocytopenia in a patient presenting for coronary artery bypass grafting. Br J Anaesth 2000 ;84(5):640-2 6. Bragnani G, Bianconcini G, Brogna R, Zoli G. Pseudothrombocytopenia. Clinical comment on 37 cases. Minerva Med 2001 ;92(1):13-7 讨论议题： 1.请广大血液学工作者及有关专家教授协助解答发生此现象的机理。 2.在日常工作中如何发现这种问题。

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Am J Hematol 1995 Oct;50(2):103-9 EDTA-dependent pseudothrombocytopenia: a clinical and epidemiological study of 112 cases, with 10-year follow-up. Bizzaro N. Laboratory of Clinical Pathology, Ospedale Civile, Venice, Italy. In the past 10 years, we have observed 112 cases of EDTA-dependent pseudothrombocytopenia (PTCP) due to in vitro platelet clumping at room temperature. 93 patients had antiplatelet antibodies (48 IgM, 30 IgG, 3 IgA, and 12 had two different isotypes concomitantly). In 20% of patients, the presence of IgM antibodies characteristically accompanied platelet agglutination also at 37 degrees C, and in citrated blood. The phenomenon was not age or sex related, nor was it associated with any particular pathology or use of specific drugs, and was present in both healthy subjects and patients with various diseases. Flow cytofluorimetric analysis of CD5-positive B cells, which are responsible for autoantibody production, did not demonstrate any changes in the percentage and absolute number of this lymphocyte subset. Average follow-up was 5 years (6 months-10 years); however, previous clinical records disclosed that PTCP was present for more than 15 years in four cases, and more than 20 years in three others, with no clinical manifestation of disease. This study confirms that EDTA-dependent PTCP is a phenomenon related to the presence of natural autoantibodies with antiplatelet activity, devoid of pathological significance. Its clinical interest resides in the need for its prompt and certain recognition in order to avoid unnecessary examinations and therapeutic interventions. The best and most rapid technique for obtaining accurate platelet counts in PTCP subjects is to collect and examine EDTA blood at 37 degrees C; however, clumping will still be present in about 20% of these cases, and even in citrated blood. To obviate this phenomenon, blood should be collected in ammonium oxalate, and platelets counted in a Burker chamber. PMID: 7572988 [PubMed - indexed for MEDLINE]

Minerva Med 2001 Feb;92(1):13-7 Pseudothrombocytopenia. Clinical comment on 37 cases. Bragnani G, Bianconcini G, Brogna R, Zoli G. Azienda USL di Ferrara, Ospedale di Cento, Divisione di Medicina Interna, Casa di Cura Villa Verde, Reggio Emilia, Italy. BACKGROUND: Pseudothrombocytopenia (PTCP) is characterized by in vitro EDTA-, pH-, temperature- and time-dependent clumping which gives rise to spurious piastrinopenia at platelet count in automatized analyzers. It is caused by serum immunoglobulins recognizing some cryptoantigens on the platelet surface membrane. Aim of this study was to evaluate the prevalence of PTCP in a series of patients and its clinical significance. METHODS: From all the inpatients, in Internal Medicine Division, during 29 months, we have considered as PTCP the thrombocytopenias persistent in EDTA and contemporaneously, missing with ACD at the automatized counter, after microscopic examination. Then we estimated: PTCP rate in regard to all patients, sex, age and morbid associations both in PTCP group and in all patients. These frequences were compared with the c-square test. RESULTS: 37 cases of PTCP are observed from a cohort of 2922 inpatients (1.26%): 23 were males, 17 females; median age was 73.7+/-11.2. The frequency of the following associations was significantly higher in the PTCP group: solid tumors in 9/37 (24.3%), myelo- and lymphoproliferative syndromes in 7/37 (18.9%), autoimmune disease in 4/37 (10.8%). CONCLUSIONS: This study suggests that PTCP is one of the more frequent thrombocytopenias: it is important to identify it, to avoid clinical and therapeutic mistakes. Moreover PTCP, in our study, is often correlated with important diseases. We can conclude that in hospitalized old patients, PTCP could represent a signal to search more severe illnesses. PMID: 11317133 [PubMed - in process]

Scand J Clin Lab Invest 1994 Nov;54(7):567 Association of pseudothrombocytopenia and pseudoleukopenia: evidence for different pathogenic mechanisms. Moraglio D, Banfi G, Arnelli A. Laboratorio di Analisi Chimico-Cliniche e Microbiologia, Ospedale SS. Annunziata, U.S.S.L. 61, Savigliano (CN), Italy. A case of spurious automated leukocyte and platelet counts due to EDTA-dependent platelet-neutrophil agglutination is described. Whole blood anticoagulated with K3EDTA, sodium citrate and lithium heparin was analysed at short time intervals up to 6 h from sampling at 37 degrees C and at room temperature (RT = 27 degrees C). A phenomenon of platelet clumping occurred at both temperatures with all the anticoagulants (pseudothrombocytopenia), while platelet-granulocyte agglutination was present only with EDTA at RT. Aggregates consisting of up to 80 neutrophils were seen on the blood smear. The contemporary presence of platelet clumping caused a reduction of WBC count of only 25% the initial, while leukocyte differential was markedly altered (pseudolymphocytosis). Further experiments were performed mixing plasma and serum of the patient with packed cells (PC) from a normal donor in the presence of different anticoagulants and at various dilutions and temperatures. Platelet-neutrophil agglutination occurred only in the presence of EDTA at temperatures lower than 37 degrees C, and was abolished by plasma dilutions from 1:8 onwards. Similarly, it was inhibited by incubation with dithiothreitol (DTT), in contrast with platelet clumping. The latter phenomenon was triggered by an EDTA concentration lower than that necessary to cause platelet-neutrophil agglutination (0.5 mg ml-1 vs. 0.77 mg ml-1). Obtained results suggest the causal association of 2 different phenomena, both transferable to normal cells by means of patient plasma and serum. In the article the pathogenetic implications of the case are discussed. PMID: 7939367 [PubMed - indexed for MEDLINE] ..

Panminerva Med 2000 Jun;42(2):155-7 EDTA-dependent pseudothrombocytopenia in a case of liver cirrhosis. Matarazzo M, Conturso V, Di Martino M, Chiurazzi F, Guida G, Morante R. Department of Internal Medicine, Federico II University Medical School, Naples, Italy. Pseudothrombocytopenia (PTCP) is the consequence of an EDTA-activated platelet agglutination, resulting in a spuriously low platelet count. We report the case of a 54-year-old man with EDTA-dependent PTCP associated with liver cirrhosis. He couldn't undergo endoscopic examination and dental care for two years because of a previous diagnosis of severe thrombocytopenia secondary to liver cirrhosis. Lack of PTCP recognition may lead the physician to misdiagnosis and mismanagement of the patient. PMID: 10965778 [PubMed - indexed for MEDLINE]

Br J Anaesth 2000 May;84(5):640-2 Anticoagulant-induced pseudothrombocytopenia in a patient presenting for coronary artery bypass grafting. Wilkes NJ, Smith NA, Mallett SV. Department of Anaesthesia, Royal Free Hampstead NHS Trust, London, UK. A 73-yr-old man with severe ischaemic heart disease presented for coronary artery bypass grafting. His preoperative platelet count, obtained from an ethylene diamine tetraacetic acid (EDTA) sampling bottle, was 61 x 10(9) litre-1, but he had no history of bleeding problems. Previous platelet counts demonstrated results ranging from 16 x 10(9) litre-1 to 254 x 10(9) litre-1 with variable degrees of in vitro platelet clumping. Preoperative thrombelastography reflected a normal coagulation profile. The laboratory findings and the absence of a history of haemorrhagic complications suggested a diagnosis of EDTA-dependent pseudothrombocytopenia. We present the perioperative implications of this in vitro phenomenon and methods of detecting the functional and numerical integrity of circulating platelets. PMID: 10844845 [PubMed - indexed for MEDLINE]

Clin Chim Acta 2000 Sep;299(1-2):119-28 Pseudoleukocytosis without pseudothrombocytopenia induced by the interaction of EDTA and IgG(2)-kappa M-protein. Shimasaki AK, Fujita K, Fujio S, Sakurabayashi I. Department of Clinical Laboratories, Himeji National Hospital, Honmachi, Himeji, 670-8520, Hyogo, Japan. We encountered a patient who showed ethylenediaminetetraacetic acid (EDTA)-induced pseudoleukocytosis without pseudothrombocytopenia. The patient had IgG-kappa type monoclonal (M) gammopathy. The total protein concentration was 77 g/l, and the gamma-globulin fraction containing M-protein was 23.2%. The white blood cell count of the patient's blood anti-coagulated with EDTA was 52300/microl as determined using an automated counter, but was within normal limits when counted manually by light microscopy using a hemacytometer. Large amounts of a transparent substance were observed on blood smears, and white precipitates were formed by an interaction of the patient's serum with EDTA. Immunofixation electrophoresis showed these precipitates to be of the IgG(2)-kappa type M-protein. Western blotting analysis showed that the IgG molecules had a molecular mass of 155 kDa and were composed of two gamma-chains of approximately 53 kDa and two kappa-chains of 27 kDa. Pseudoleukocytosis was also observed when the patient's blood was anti-coagulated with O, O'-bis(2-amino-ethyl)-ethyleneglycol-N,N,N',N'-tetraacetic acid (EGTA) or sodium citrate, but not with lithium heparin. The present case seems to be the first report of pseudoleukocytosis induced by the interaction of EDTA and IgG(2)-kappa type M-protein. PMID: 10900298 [PubMed - indexed for MEDLINE]

· Ann Hematol 2000 Apr;79(4):226/ Ann Hematol 2000 Mar;79(3):161-4 Sudden onset of EDTA-dependent pseudothrombocytopenia after therapy with the glycoprotein IIb/IIIa antagonist c7E3 Fab. Stiegler H, Fischer Y, Steiner S, Strauer BE, Reinauer H. Institut fur Klinische Chemie und Palkobiochemie, Universitatsklinikum der RWTH Aachen. Hugo.Stiegler@post.rwth.aachen.de The development of thrombocytopenia following exposure to the platelet glycoprotein (GP) IIb/ IIIa receptor antagonist abciximab (c7E3 Fab, ReoPro) is associated with adverse clinical outcome and excessive bleeding. Pseudothrombocytopenia is an important differential diagnosis in sudden onset of thrombocytopenia in a patient treated with c7E3 Fab. We report on a case of documented sudden onset of EDTA-dependent pseudothrombocytopenia in a 63-year-old woman who was admitted for emergency coronary intervention. Four hours after bolus administration of c7E3 Fab, the platelet concentration in EDTA-anticoagulated blood decreased from 385 x 10(9)/l to 119 x 10(9)/l, and it showed a further decrease to 57 x 10(9)/l at the end of a 12-h infusion. Despite no warnings or abnormalities of the automated cell counter, platelet aggregates were observed by microscopic evaluation of the blood smear. Repeated platelet counts in citrate-anticoagulated samples revealed platelet concentrations within the reference range. EDTA-dependent pseudothrombocytopenia due to therapy with c7E3 Fab is an important differential diagnosis that needs to be excluded rapidly from other causes of thrombocytopenia to avoid unnecessary further examinations, discontinuation of therapy, or even initiation of inappropriate therapy. PMID: 10803940 [PubMed - indexed for MEDLINE]

Intensive Care Med 2000 Feb;26(2):218-20 Transient EDTA-dependent pseudothrombocytopenia in a patient with sepsis. Mori M, Kudo H, Yoshitake S, Ito K, Shinguu C, Noguchi T. Department of Anesthesiology and Intensive Care Medicine, Oita Medical University, Hasama-machi, Japan. mmori@oita-med.ac.jp Ethylenediaminetetraacetic acid-dependent pseudothrombocytopenia (EDTA-PTCP) is the phenomenon of a spurious low platelet count due to antiplatelet antibodies that cause platelet clumping in blood anticoagulated with EDTA. We describe a case of EDTA-PTCP that appeared transiently with the development of sepsis. A 50-year-old man underwent Bentall's aortic root replacement for acute aortic dissection with aortic insufficiency. Postoperatively the patient suffered paralytic ileus followed by methicillin-resistant Staphylococcus aureus enteritis and septicemia with endotoxemia. EDTA-PTCP appeared with the development of sepsis, and disappeared with its resolution. To avoid incorrect diagnoses and inappropriate treatment, EDTA-PTCP should always be considered as a possible cause of reported low platelet counts, even in patients with sepsis. PMID: 10784313 [PubMed - indexed for MEDLINE]

Wien Klin Wochenschr 2000 Feb 11;112(3):138-41 A case of pseudothrombocytopenia after infusion of abciximab in vivo and anticoagulant-independent platelet clumping after rechallenge with abciximab in vitro. Kozak M, Dovc T, Rozman P, Blinc A. Department of Angiology, University Medical Centre Ljubljana, Slovenia. A 45-year old man was treated for unstable angina pectoris with percutaneous transluminal angioplasty and stenting of his left anterior descending coronary artery. The procedure was followed by infusion of abciximab. The patient's automated platelet count in an EDTA-anticoagulated blood sample at admission to the hospital was normal, but dropped to 5 x 10(9)/l three hours after the procedure. The infusion of abciximab was stopped and the patient received platelet transfusions although there were no signs of bleeding. Two days later his platelet count was still low (37 x 10(9)/l) in an EDTA-anticoagulated blood sample, but normal (193 x 10(9)/l) in a heparin-anticoagulated sample. Platelet clumps were present only in the sample anticoagulated with EDTA, and pseudothrombocytopenia was diagnosed. The patient's recovery was uneventful. At follow-up visits four months and one year after discharge from hospital, the patient's blood samples were anticoagulated with three different anticoagulants: EDTA, citrate and heparin. The platelet count was normal in all three samples but after mixing with abciximab in vitro it dropped profoundly due to platelet clumping, regardless of the choice of the anticoagulant. Our report raises two points: (a) one needs to consider the possibility of pseudothrombocytopenia in a patient with a low automated platelet count after infusion of abciximab but without signs of bleeding, and (b) the in vitro results suggest that our patient who had initially responded to abciximab with pseudothrombocytopenia could develop true thrombocytopenia after repeated exposure. PMID: 10729966 [PubMed - indexed for MEDLINE]

Scand J Clin Lab Invest 1997 Nov;57(7):629-36 Screening for EDTA-dependent deviations in platelet counts and abnormalities in platelet distribution histograms in pseudothrombocytopenia. Bartels PC, Schoorl M, Lombarts AJ. Department of Clinical Chemistry, Haematology and Immunology, Medical Centre Alkmaar, The Netherlands. Screening for pseudothrombocytopenia caused by in vitro platelet clumping has been performed in 45,000 subjects attending a general hospital. In our region, the observed prevalence of EDTA-induced pseudothrombocytopenia in blood samples with an initial platelet count below 150 x 10(9)/l was estimated to amount to 0.1%. EDTA-induced pseudothrombocytopenia was confirmed by detection of platelet aggregates by means of microscopic evaluation from the blood smear. In routine investigations, pseudothrombocytopenia could be highly suspected when the Sysmex NE 8000 showed characteristic peculiarities in the white blood cell (WBC) scattergram and histogram. Platelet aggregation is avoided in such cases by the use of citrate as an anticoagulant instead of EDTA. Pseudothrombocytopenia was detected in 46 subjects. As a screening test for pseudothrombocytopenia, increased cut-off values derived from the WBC histogram demonstrated 90% sensitivity and 100% specificity. Automated flagging for platelet clumps, deviations reflecting MPV, or PDW abnormalities revealed lower scores with respect to sensitivity. Ann Hematol 1997 Jun;74(6):283-5 Documented sudden onset of pseudothrombocytopenia. Gschwandtner ME, Siostrzonek P, Bodinger C, Neunteufl T, Zauner C, Heinz G, Maurer G, Panzer S. Department of Cardiology, Allgemeines Krankenhaus Wien, University of Vienna, Austria. A 66-year-old male patient was hospitalized for severe heart failure. Within 3 days after admission his platelet count dropped from 148 x 10(9)/l to 3 x 10(9)/l. Pseudothrombocytopenia was diagnosed based on the platelet count of 3 x 10(9)/l in K3-EDTA anticoagulated blood as opposed to 110 x 10(9)/l in sodium citrate. Platelet reactive antibodies were not detectable. To the best of our knowledge, this is the first report of a documented onset of pseudothrombocytopenia. PMID: 9236514 [PubMed - indexed for MEDLINE]

Nihon Rinsho Meneki Gakkai Kaishi 1997 Apr;20(2):139-44 A case of Sjogren's syndrome associated with EDTA-dependent pseudothrombocytopenia. [Article in Japanese] Hosokawa T, Hinoda Y, Imai K. Department of Internal Medicine, Ashibetsu Municipal Hospital. A 69-year-old woman was admitted to Department of Orthopedic Surgery in our hospital because of lumbago on April 4, 1995. Since laboratory data showed thrombocytopenia (platelet count 2.1 x 10(4)/mm3) on admission, she was transferred to Department of Internal Medicine for further examination on April 11. She noticed abnormal taste and showed remarkable sicca symptoms. Schirmer test, gum test and electrogustometry were positive, and parotid sialogram findings and histology of minor salivary glands of the lip were compatible with those of typical Sjogren's syndrome. Thus, she was diagnosed as Sjogren's syndrome. Although the antibodies to SS-A/SS-B were negative in her serum, anti-nuclear and anti-centromere antibodies were strongly positive (x1280). Serum IgM level was increased. The decreased platelet count was observed when EDTA was used as anticoagulant. The binding activity of the anti-platelet antibody activated by EDTA was dependent on temperature. Its immunoglobulin class was shown to be IgM by enzyme-labelled antibody method. We here report a case of Sjogren's syndrome associated with EDTA-dependent pseudothrombocytopenia. PMID: 9178972 [PubMed - indexed for MEDLINE]

Med Clin (Barc) 1996 Nov 30;107(19):721-5 [Isolated thrombocytopenia in pregnancy. Etiopathogenic study and therapeutic approach in 60 patients]. [Article in Spanish] Altes A, Muniz-Diaz E, Pujol-Moix N, Mateo J, Fontcuberta J, Parra J, Brunet S, Madoz P. Departamento de Hematologia, Hospital de la Santa Creu i Sant Pau, Barcelona. BACKGROUND: We analyze the etiopathogenesis and clinical and immunohematological characteristics of 60 pregnant women with isolated thrombocytopenia (TP) (platelet count < 150 x 10(9)/l); and the frequency of TP and hemorrhagic complications in their newborn. We suggest the therapeutic approach for each maternal TP type. PATIENTS AND METHODS: We performed: clinical history, platelet count (EDTA K3, sodium citrate, microscopic exam) and investigation of antiplatelet antibodies (immunofluorescence) in all pregnant women. A familial history and ultrastructure of platelets were studied when hereditary macrothrombocytopenia (HM) was suspected. A Levine's test of homogenicity of variances was applied to compare the mean platelet count in each diagnostic group. A linear regression between maternal and newborn platelet counts was performed. RESULTS: In 37 thrombocytopenic women (62%) no antiplatelet antibodies were found, and the clinical history was negative for previous TP or abnormal bleeding. Four patients (7%) were diagnosed as pseudothrombocytopenia EDTA-mediated, and eight (13%) of HM. Finally, an autoimmune etiology was suspected in 11 women (18%) and antiplatelet antibodies were detected in 9. Mean platelet counts of mother with immune TP did not show statistically significant differences with other diagnostic groups. Abnormal bleeding was not observed in any patient or newborn. There was no correlation between platelet counts of mothers and newborns. Platelet count obtained by skull bone punction led to unnecessary caesarians in four cases. CONCLUSIONS: The frequency of immune thrombocytopenia in pregnant women is low (18%). There is a high prevalence of benign TP (62%). The pseudothrombocytopenias and HM are frequent findings (20%), and special care is advisable in these cases to avoid unnecessary therapeutic procedures. PMID: 9082088 [PubMed - indexed for MEDLINE]

1: Am J Clin Pathol 1995 Jan;103(1):103-7 EDTA-dependent pseudothrombocytopenia. Association with antiplatelet and antiphospholipid antibodies. Bizzaro N, Brandalise M. Laboratorio di Patologia Clinica, Ospedale Civile, S.Dona di Piave (Venice), Italy. In a study of 88 patients with EDTA-dependent pseudothrombocytopenia (PTCP), EDTA-dependent antiplatelet antibodies were seen in the sera of 72 (81.8%) patients (44 IgM, 25 IgG, and 3 IgA). The same sera also were tested for anticardiolipin antibodies (aCL), and 56 (63.6%) patients had sera that also were reactive for aCL (33 IgM, 21 IgG, and 2 IgA). The 16 patients who were negative for antiplatelet antibodies also were negative for aCL antibody. Overall concordance between antiplatelet and aCL antibodies was 82.9%; the correlation between antiplatelet and aCL antibody isotype distribution was 82.1%. Following cardiolipin absorption, most of the PTCP-sera were negative for antiplatelet activity, and no longer reproduced platelet clumping when incubated with normal blood. This finding showed that the antiplatelet antibodies cross-reacted with negatively charged phospholipids. However, after absorption on normal platelets, complete inhibition of aCL activity was observed in 34 (60.7%), and partial inhibition in 14 of the 56 patients who were aCL positive. These findings support the hypothesis that antibody subpopulations (naturally occurring autoantibodies) directed against negatively charged phospholipids can bind to antigens modified by EDTA on the platelet membrane, and may be responsible for PTCP genesis. PMID: 7817934 [PubMed - indexed for MEDLINE]

Scand J Haematol 1975 Oct;15(3):161-70 Pseudothrombocytopenia due to platelet aggregation and degranulation in blood collected in EDTA. Mant MJ, Doery JC, Gauldie J, Sims H. Three patients are described in whom platelet aggregation and/or degranulation occurred in blood collected into EDTA. These changes resulted in spurious thrombocytopenia and morphological changes similar to those observed in some thrombocytopathies. The abnormalities were dependent on the presence of EDTA and did not occur in citrate, oxalate or heparin anticoagulants. In two patients the abnormality was shown to be due to a plasma factor which was not IgG, IgM, fibrinogen or albumin. The most likely explanation is that these patients have an unidentified abnormal plasma component which, on exposure to EDTA, develops 'anti-platelet activity'. Althought relatively uncommon a prospective study of the incidence of these phenomena indicates that they are probably more common than either platelet cold agglutinins or platelet satellitism. They have practical significance with respect to the diagnosis of thrombocytopenia and also to the interpretation of abnormal platelet morphology. PMID: 812172 [PubMed - indexed for MEDLINE]

Am J Clin Pathol 1979 Dec;72(6):1005-8 Pseudothrombocytopenia due to agglutinins. Veenhoven WA, van der Schans GS, Huiges W, Metting-Scherphuis HE, Halie MR, Nieweg HO. Pseudothrombocytopenia may have any of a number of causes, one of which is agglutination in vitro. This phenomenon was found in samples of blood from six patients. A serum factor responsible for the agglutination was demonstrated. The factor was dependent upon the presence of EDTA and was more active at room temperature than at 37 C. It could be identified as an IgM immunoglobulin in four cases. In the other two cases definite characterization was not possible, but there was some evidence in favor of an IgM factor. All six patients had elevated serum IgM levels, but they had different and unrelated clinical disorders. PMID: 117695 [PubMed - indexed for MEDLINE]

Dtsch Med Wochenschr 1985 Mar 29;110(13):492-5 [Pseudo thrombocytopenia--an error in the determination of thrombocyte count]. [Article in German] Rosenkranz B, Wisser H, Bode JC. Automated counting resulted in erroneously low numbers of platelets (pseudothrombocytopenia) in three patients. The machine-derived values (ELT-8) were initially 30 000, 8000 and 8000/microliter, respectively. Numerous agglutinates could be demonstrated in the counting chamber. Whereas counting in the first patient showed a real value with an average of 252 000/microliter both the other preparations could not be counted due to numerous agglutinates. The artificially low number of platelets in the counter can thus be explained by lack of recognition as platelets due to the size of the in vitro formation of agglutinates. Should these be of the size of white cells leukocytosis may be suggested. Formation of agglutinates was not limited to use of EDTA as anticoagulant but could also be observed with other anticoagulants such as heparin and citrate. For prevention of superfluous and potentially dangerous therapeutic steps the diagnosis of platelet deficiency should be ascertained in any case by additional determination of the platelet count in the counting chamber. PMID: 3920040 [PubMed - indexed for MEDLINE]

不知道张时民老师会不会看到我下面的话。 advia120 应该有血小板凝集的警告。当PLT值异常低的话，检验人员就应该询问病人病史并应该制片镜检。这样的话，就会在门诊发现由于抗凝剂所致的PLT假性减少了。

是EDTA-K2和EDTA-K3，用于抗凝剂会更好些？

EDTA-K3要好于EDTA-K2