Effect of 3.2%vs3.8% Sodium Citrate Concentration on Routine Coagulation Testing

Abstract

The effects of 3.2% and 3.8% sodium citrate concentration on the results of routine coagulation assays (prothrombin time [PT] and activated partial thromboplastin time [aPTT]) were evaluated by means of two sets of reagents, one responsive and the other nonresponsive. Five groups were entered in the study: healthy volunteers; outpatients receiving stable oral anticoagulant therapy; and hospitalized patients receiving intravenous (IV) heparin therapy, both IV heparin and oral anticoagulant therapy, or no anticoagulant therapy. With use of nonresponsive PT and aPTT reagents, varying the citrate concentration has little clinical significance except in patients receiving IV heparin therapy. In contrast, when responsive PT and aPTT reagents are used, the concentration of Many preanalytic variables may affect the results of routine coagulation assays. To improve the precision and accuracy of laboratory testing, it is important to identify these variables and realize their potential effects on testing. Preanalytic variables pertinent to routine coagulation testing can be classified into three major categories: specimen collection, specimen transportation and storage, and specimen processing. Variables associated with specimen collection alone are numerous. Some have little to no effect; others significantly affect assay results. Few studies document the influence of preanalytic variables. Such studies are difficult to reference; many have been published in nonpeer-reviewed publications such as Manuscript received May 15, 1996; revision accepted August 9, 1996.A d d r e s s reprint requests to Dr Adcock: D e p a r t m e n t of Pathology, 16601 E Centretech Pkwy, Aurora, CO 80011.sodium citrate anticoagulant has a significant effect on assay results. Eighteen percent of samples from patients receiving stable oral anticoagulant therapy demonstrated a change of less than 0.7 INR (International Normalized Ratio) units between citrate concentrations. Nineteen percent of patients receiving IV heparin therapy had a greater than 7-second difference when aPTT results were compared. These data demonstrate that citrate concentration affects the results of coagulation tests. On the basis of these data, it is recommended that 3.2% citrate be used for all coagulation tests.

Un temps de céphaline activée élevé n’est pas associé à un rebond d’héparine après une chirurgie cardiaque

“…[41][42][43] Apart from the use of heparin, hirudin analogues, and argatroban, 42 the APTT may also be prolonged by a deficiency of coagulation factors (congenital or acquired), including lupus anticoagulant, monoclonal gammopathy, and dysfibrinogenemia. An APTT ratio of 1.5-2.5 times the control value equates to protamine titrated heparin levels of 0.2-0.4 U Á mL -1 .…”

American Heart Association/American College of Cardiology Foundation Guide to Warfarin Therapy

“…108 The concentration of citrate used to anticoagulate plasma affects the INR. 109,110 In general, higher citrate concentrations (Ն3.8%) lead to higher INR values, 109 and underfilling the blood collection tube spuriously prolongs the PT because excess citrate is present. Using collection tubes containing 3.2% citrate for blood coagulation studies can reduce this problem.…”

Anormal coagulation test results in the pediatric patient without the bleeding: A case report

“…Bazı çalışmalarda, yüksek hemotokrit değerlerine sahip örneklerde sitrat seviyelerinin yükselmesini simüle etmek için yetersiz doldurulmuş %3,2'lik ve %3,8'lik sitratlı tüp kullanmıştır. Bu çalışmalarda, hematokritin PZ ve aPTZ üzerine %3,8'lik sitratlı tüplerdeki beklenen etkinin çok daha fazla olduğunu gösterilmekle birlikte, her iki tüpte de anlamlı etki tespit edilmiştir (2)(3)(4)(5)(6) . Marlar ve ark.…”

“…Direkt ve indirekt yöntemlerle yapılan çalışmalara dayanarak, yüksek hematokrit değerine sahip kan örnekleri için kullanılan sitrat miktarının ayarlanması önerilmektedir (2)(3)(4)(5)(6) . Olgumuzda yüksek hematokritli çocuk hastanın koagülasyon testlerinde tanı ve tedaviyi etkileyebilecek değişiklikler literatür eşliğinde tartışılmıştır.…”