Congenital thrombophilia among patients with venous thromboembolism.

During a 3-year period we studied 393 adult patients (382 of whom were unrelated) with a history of acute venous thromboembolism. A congenital deficiency state known to predispose to thrombosis was found in 27.2%. Of these, most were due to deficiencies of protein C (9.2%), protein S (7.6%), antithrombin III (5%) or to increased plasma PAI-1 concentration (3.1%) which, in the absence of any known factor that predisposes towards thrombosis, results in a diminished fibrinolytic activity. There was a characteristic pattern between the age of onset (mean 34 years) of thrombosis and individual protein deficiency. Thrombosis appeared spontaneously in 73% of cases with recurrence in 80%. In contrast, in the remaining unrelated patients, 138 (35.1%) in whom venous thromboembolism was secondary and occurred at a mean age of 43 years, and in the other 140 (35.6%) who suffered thromboembolism spontaneously at a later age (mean age 55), there was no permanent protein deficiency state or alteration in fibrinolytic activity and thrombosis recurrence was lower (53.6% and 20.7% respectively). Of the 393 patients, deep vein thrombosis was the most common manifestation; however, in congenital thrombophilia, thrombosis of visceral vessels and Raynaud's syndrome (6%) were also detected.     

Compliance with recommended prophylaxis for venous thromboembolism: improving the use and rate of uptake of clinical practice guidelines

Summary.  Although several authoritative, evidence-based, guidelines for the prevention of venous thromboembolism (VTE) have been published, the use of VTE prophylaxis in routine clinical practice varies markedly. Even in orthopedic surgery, the indication for which prophylaxis is used most often, a significant proportion of surgeons do not use routine prophylaxis. When prophylaxis is used, guideline recommendations are often not followed. A number of factors may contribute to the under-use of guidelines. Physician-related factors include: a lack of awareness of, or familiarity with, the guidelines; a perception that VTE is not a significant problem or that VTE prophylaxis is ineffective; and concern about potential bleeding risks. The guidelines may also be perceived to be too complicated or difficult to apply in a routine manner. In addition, a lack of facilities or resources may also present a barrier to implementation of the guidelines. A number of strategies are being investigated in an attempt to improve compliance with guidelines for VTE prophylaxis. For example, the Investigators Against Thromboembolism (INATE) initiative has developed a simplified pocket guideline on VTE prophylaxis in orthopedic and trauma surgery in order to raise awareness of the current guideline recommendations.     

Influence of whole blood on standard curve for heparin measurement--possible heparin binding by red cells

Measurement of heparin ex vivo is usually with reference to standard curve prepared with a "spiked" normal human plasma pool (NHP). When the calibration curve was prepared by addition of heparin to whole blood before plasma separation, although the linear relationship was maintained the slope was increased in comparison to the classical standard calibration curve. It is concluded that the preparation of the calibration curve by addition of heparin to NHP may give erroneously high heparin levels in treated patients' plasma, leading perhaps to inappropriate dosage. It was also observed that when heparin was added to blood of different haematocrit (prepared by addition of washed RBC to plasma) and plasma prepared, the subsequent APTT was decreased with the fall in haematocrit; suggesting that the laboratory monitoring of heparin treatment should take into account the patient's haematocrit.     

Spurious automated red cell parameters due to cold agglutinins--a report of two cases

Although automation in hematology has resulted in improved accuracy of results, there are certain clinical conditions in which even the technologically advanced cell counters give out spurious results. It is therefore important that operators of these instruments are aware of these factitious results and the clues in the automated data that can be of help in identifying them. Two cases with spurious automated red cell parameters due to cold agglutinins are reported here.     

Use of the gel-based DiaMed-ID microtyping system for crossmatching enhances sensitivity

A host of newer techniques have been introduced over the past decade in blood bank serological testing. One such technology which has been in vogue in the west since early 1990s is the gel test. The procedures used are standardized and they provide clear and stable reactions that improve result interpretation. The principle involves the differential passage of red cell agglutinates and free red blood cells through a dextran acrylamide gel. The results are stable and may be read even after many hours. The test is easy to perform, sensitive and reproducible. We report our experience in compatibility testing with use of the DiaMed micro typing system which is based on the gel technology. Over a one year period since this technology was introduced in our blood bank, we noticed a startling 65 fold rise (p<0.0001) in the reported number of incompatible units in one year which rose from a paltry 4 (0.02%) to 260 (1.6%). We found the DiaMed system easy to use and as our findings suggest it proved to be more sensitive than the conventional tube agglutination technique.     

Cytopathology of uncommon malignant renal neoplasms in the pediatric age group

Malignant renal neoplasms are common solid tumors in pediatric oncology practice. These include the common Wilms' tumor/nephroblastoma and the uncommon neoplasms such as clear-cell sarcoma of the kidney (CCSK), rhabdoid tumor, renal-cell carcinoma, and others. The aim of this study was to describe in detail the cytopathological features of the histopathologically proven uncommon pediatric renal tumors. Aspirates from Wilms' tumor, which are mesenchyme predominant, show clusters of spindle cells associated with the matrix material. Evidence of rhabdomyoblastic differentiation may be present. CCSK, classic subtype, is characterized by round to oval cells arranged perivascularly and also in sheets and clusters intimately associated with a metachromatic matrix mucopolysaccharide material better appreciated in May-Grunwald-Giemsa (MGG)-stained smears. The cells also have more abundant cytoplasm and may show nuclear grooves. Spindle-cell pattern of CCSK is difficult to diagnose on aspiration cytology. Renal-cell carcinoma of childhood shows similar cytological features as its adult counterpart. Rhabdoid tumor of the kidney is characterized by a monomorphic population of cells with abundant cytoplasm, eccentric nuclei with prominent nucleoli. Intrarenal yolk sac tumor is a rare neoplasm and shows severely pleomorphic cells on aspiration.Awareness of these entities is important for the practicing cytopathologist. Further, non-Wilms' renal malignant neoplasms must be distinguished from the common Wilms' tumor so that appropriate chemotherapy protocols may be instituted in cases where the tumor is in an advanced stage of malignancy.