The prothrombin time (PT) represents the most commonly used coagulation test in clinical laboratories. The PT is mathematically converted to the international normalized ratio (INR) for use in monitoring anticoagulant therapy with vitamin K antagonists such as warfarin in order to provide test results that are adjusted for thromboplastin and instrument used. The INR is created using two major PT ‘correction factors’, namely the mean normal PT (MNPT) and the international sensitivity index (ISI). Manufacturers of reagents and coagulometers have made some efforts to harmonizing INRs, for example, by tailoring reagents to specific coagulometers and provide associated ISI values. Thus, two types of ISIs may be generated, with one being a ‘general’ or ‘generic’ ISI and others being reagent/coagulometer‐specific ISI values. Although these play a crucial role in improving INR results between laboratories, these laboratories reported INR values are known to still differ, even when laboratories use the same thromboplastin reagent and coagulometer. Moreover, ISI values for a specific thromboplastin can vary among different models of coagulometers from a manufacturer using the same method for clot identification. All these factors can be sources of error for INR reporting, which in turn can significantly affect patient management. In this narrative review, we provide some guidance to appropriate ISI verification/validation, which may help decrease the variability in cross laboratory reporting of INRs.

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In December 2019, a new type of coronavirus was detected for the first time in Wuhan, Hubei Province, China. According to the reported data, the emerging coronavirus has spread worldwide, infecting more than fifty‐seven million individuals, leading to more than one million deaths. The current study aimed to review and discuss the hematological findings of COVID‐19. Laboratory changes and hematologic abnormalities have been reported repeatedly in COVID‐19 patients. WBC count and peripheral blood lymphocytes are normal or slightly reduced while these indicators may change with the progression of the disease. In addition, several studies demonstrated that decreased hemoglobin levels in COVID‐19 patients were associated with the severity of the disease. Moreover, thrombocytopenia, which is reported in 5%‐40% of patients, is known to be associated with poor prognosis of the disease. COVID‐19 can present with various hematologic manifestations. In this regard, accurate evaluation of laboratory indicators at the beginning and during COVID‐19 can help physicians to adjust appropriate treatment and provide special and prompt care for those in need.

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Exosomes, as natural occurring vesicles, play highly important roles in the behavior and fate of ischemic diseases and different tumors. Secretion, composition, and function of exosomes are remarkably influenced by hypoxia in ischemic diseases and tumor microenvironment. Exosomes secreted from hypoxic cells affect development, growth, angiogenesis, and progression in ischemic diseases and tumors through a variety of signaling pathways. In this review article, we discuss how hypoxia affects the quantity and quality of exosomes, and review the mechanisms by which hypoxic cell‐derived exosomes regulate ischemic cell behaviors in both cancerous and noncancerous cells.

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Objective: First-time blood donors are the most common group of blood donors. They usually have different motivations for blood donation, some of which provoke the donors to hide risk factors of transfusion-transmissible infections (TTIs). Therefore, detection of TTIs among first-time donors is crucial and can decrease the rate of TTIs among blood recipients. This study aimed to evaluate the prevalence of TTIs among first-time donors in the transfusion center of Kohgiluyeh and Boyer-Ahmad Province (KBTC), Iran. Materials and Methods:This retrospective study was conducted with volunteer blood donors in 2004-2014 in the KBTC. Various data, including sex, confidential unit exclusion (CUE), previous donation history, and the laboratory findings of confirmatory tests, were extracted from blood donor software. Data were analyzed by SPSS using the chi-square test.Results: Among 198,501 blood donors, 52,527 (26.46%) were firsttime donors, while 145,974 donors (73.54%) were repeat and regular donors. Most of the donors (94.5%) were male, while a minority (5.5%) were female. The CUE option was chosen by 2,237 (1.13%) donors. The incidence of hepatitis B surface antigen (HBsAg) and hepatitis C virus (HCV) was 247 (0.13%) and 134 (0.07%) among the entire study population, respectively. Three donors (0.002%) had confirmed human immunodeficiency virus (HIV), while none of the blood donors were positive for syphilis. Most of the donors with positive HBsAg (95.8%), HCV (86.6%), and HIV (100%) infection were first-time donors. Conclusion:Since TTIs are more common among first-time blood donors than regular and repeat donors, special considerations should be taken into account for this common group of blood donors.Amaç: Kan donörlerinin büyük çoğunluğunu ilk kez kan veren donörler oluşturmaktadır. Bu kişilerin genellikle kan vermek için farklı motivasyonları vardır ve bu da vericilerin transfüzyon ilişkili enfeksiyonları (TTI) saklaması açısından risk oluşturur. Bu nedenle ilk kez verici olanlarda TTI'ları tespit etmek çok önemlidir ve böylece kan alıcılarında TTI'lar azaltılabilir. Bu çalışmada amaç İran'da Kohgiluyeh ve Boyer-Ahmad Bölgesi (KBTC) transfüzyon merkezindeki ilk kez verici olan kan donörlerinde TTI prevelansının araştırılmasıdır. Gereç ve Yöntemler:Bu çalışma, KBTC'de 2004-2014 yılları arasında gönüllü kan vericilerinin dahil edildiği retrospektif bir çalışmadır. Cinsiyet, gizli ünite dışlaması (CUE), daha önceki kan bağışları, ve doğrulama testlerinin laboratuvar bulguları gibi veriler, kan vericileri yazılımından elde edilmiştir. Elde edilen veriler ki-kare testi kullanılarak SPSS ile değerlendirilmiştir. : 198,501 kan vericisinden 52,527'i (%26,46) ilk kez kan veren donörler, 145,974'i ise düzenli olarak kan verenler veya daha önce kan vermis olanlardı (%73,54). Vericilerin çoğu erkekti (%94,5), kadın verciler azınlıktaydı (5,5%). CUE seçeneği 2,237 (%1,13) verici tarafından kullanılmıştı. Bütün çalışma grubunda hepatit B yüzey antijeni (HBsAg) ve hepatit C virüsü (HCV) sıklığı sırasıyla 247 (%0,13) ve 134 (%0,0...