Influence of donor characteristics on the milk donation volume and microbiological quality of donated human milk in first 3 years of work of the Croatian human milk bank-retrospective observational study.

OBJECTIVES: Donated human milk is the best possible alternative when mother's own milk is not available. The aim of this study is to investigate whether there are differences in the milk donation volumes and microbiological quality of donated milk depending on human milk donors (HMDs) characteristics. METHODS: We analyzed data on the HMDs who donated milk in the first three years of work of human milk bank (HMB) - November 2019 to January 2023. The data on the volume of donated milk in L and suitable microbiological quality assessed by the number and isolated species of bacteria were collected from questionnaires filled out by HMDs and documentation administered by HMB employees and are presented using descriptive and comparative statistics. RESULTS: Two hundred HMDs were included in this study. The majority of them are between 26 and 35 years of age, reside in capital city or the surrounding county, have given birth to a full-term child vaginally, and express surplus milk through a breast pump. Donor mothers of preterm born infants (14.5 %) donated greater quantities, there is statistically significant difference in the median of volume of milk donated (9.6 vs. 6.4, p=0.026). Milk expressed manually shows better results in microbiological quality (median percentage 100 vs. 82 vs. 100, p=0.040), while by comparing other characteristics of the donors, no difference was found between the groups. CONCLUSIONS: It is important to be aware of the characteristics of previous HMDs in order to direct the HMB future promotional and educational activities.

Cryopreserved human heart valve allografts: a ten-year single centre experience.

This study provides an overview of tissue banking activities at the Croatian Cardiovascular Tissue Bank (CTB) during past ten years and presents the outcomes of cryopreserved heart valve allografts (CHAs) use in different patient groups. From June 2011 until December 2021, 75 heart donations were referred to CTB: 41 recipient of heart transplant (RHT), 32 donors after brain death (DBD) and 2 donors after circulatory death (DCD) donations. Processing resulted in 103 valves of which 65 met quality requirements for clinical use. Overall tissue discard rate was 37%. The most frequent reasons for discard were inadequate morphology (12%) in RHT donations and microbiological contamination (19%) in DBD donations. Altogether, 38 CHAs were transplanted to 36 patients. Recipients were divided in three groups; infective endocarditis (IE), non-infectious heart disease and congenital heart disease group. In the IE group, the 30-day, 1-year and 3-year survival was 71%, 53% and 47%, respectively. Freedom from re-operation due to all graft-related causes was 76% and due to structural valve deterioration 88%. There were no cases of graft reinfection. In the congenital heart disease group CHAs were predominantly (94%) used for right ventricular outflow tract reconstruction and 88% of patients recovered without graft-related complications. At present, the number of demands for CHAs at CTB considerably outweighs their availability.

The appropriateness of platelet transfusions in hematological patients and the potential for improvement.

BACKGROUND: Hematology patients are intensive platelet users. In clinical practice, a substantial proportion of platelet (PLT) transfusions are routinely administered outside the guidelines despite compelling evidence for recommendations. Those unnecessary PLT transfusions are an unjustified extra burden on a scarce healthcare resource and may also be detrimental to the patients. This study aims to evaluate indications and assess the appropriateness of PLT transfusion, as well as to identify common discrepancies and propose modalities for better compliance with guidelines. MATERIAL AND METHODS: The audit of all PLT orders for adult hematological inpatients was conducted over 2 months. The assessment was performed using guidelines for PLT transfusion. Patient demographic, clinical, and transfusion data were collected from hospital electronic medical records. RESULTS: Based on 286 PLT orders, 344 PCs were transfused to 67 patients: 235 (82.2%) prophylactical due to low PLT count, 34 (11.9%) preprocedural and 17 (5.9%) therapeutic. Overall, 105 (36.77%) PLT transfusions were inappropriate: 78 (33.2%) of all prophylactic PLT transfusions due to low PLT count, 17 (50%) off all preprocedural and 10 (58.8%) of all therapeutical transfusion. The major reason for PLT transfusion inappropriateness was transfusion above the recommended threshold. Double units of PCs were transfused in 36.7% of all PLT transfusions and 32.4% of them were considered inappropriate. CONCLUSION: Our audit of PLT transfusion practice found a large proportion of inappropriate PLT transfusions. Based on the most common deviations from the guidelines a variety of targeted measures for improvement are proposed.

Propensity-score matched comparison between minimally invasive and conventional aortic valve replacement.

AIM: To evaluate the impact of minimally invasive aortic valve replacement (mini-AVR) on clinical outcomes in comparison with the gold standard. METHODS: We retrospectively reviewed the records of all patients who underwent isolated AVR at the University Hospital Center Zagreb from 2010 to 2020. Patients undergoing mini-AVR were compared with patients undergoing conventional AVR (fs-AVR). The primary outcome measure was blood product consumption. Propensity score matching was used to create a balanced covariate distribution across treatment groups. Additionally, we compared the contemporary outcomes with a historical control. RESULTS: The final sample consisted of 1088 patients. In the unmatched cohorts, mini-AVR patients were younger (65±12 vs 68±10 years, P<0.001) and had lower risk profiles (EuroSCORE2 2.8±2.0 vs 3.5±3.1, P=0.003). After matching, mini-AVR patients required less blood transfusion than fs-AVR patients (270 [0-790] vs 510 [0-970] mL, P=0.029). The incidences of stroke, dialysis, new AV block, and mortality were comparable. Cross-clamp times were longer in the mini-AVR group (71 [60-87] vs 66 [53-83] minutes, P=0.013). Outcomes were improved in the contemporary mini-AVR era compared with our early mini-AVR experience across multiple metrics. Blood product consumption was reduced in the latter tercile of experience (0 [0-520] vs 500 [0-1018] mL, P<0.001), and the operation was performed more expeditiously (cross-clamp times: 63 [54,80] vs 74 [62,88] minutes, P<0.001) in comparison with earlier periods. CONCLUSIONS: We showed that mini-AVR was associated with less blood product requirement than conventional surgery. Our data supports wider adoption of minimally invasive techniques in dedicated centers of excellence.

Severe intracranial haemorrhage in neonatal alloimmune thrombocytopenia due to antibodies against human platelet antigen 1b: Case report and literature review.

Fetal/neonatal alloimmune thrombocytopenia (FNAIT) is a rare life-threatening disorder, leading to severe thrombocytopenia and potentially bleeding, with intracranial haemorrhage (ICH) being the most serious complication. We report on a FNAIT case with fourth-degree ICH that arose due to antibodies against human platelet antigen (HPA)-1b. The male infant, born to an otherwise healthy mother, presented with severe signs of ICH soon after delivery. Since only moderate thrombocytopenia was noted and there were no active signs of bleeding, the infant did not receive intravenous immunoglobulins (IVIg) or platelet transfusion. Spontaneous recovery of platelets was noted on the eighth day of life, but permanent neurological impairment remained as a consequence of ICH. We report the results of HPA and human leukocyte antigen (HLA) antibodies in the mother's and the infant's sera, the family's HPA genotype and the mother's HLA genotype, and summarise previously described cases of FNAIT due to anti-HPA-1b antibodies in the literature. FNAIT with severe ICH due to anti-HPA-1b antibodies is rarely diagnosed. An association between HLA genes and sensitization to HPA-1b antibodies was not demonstrated. The severity of FNAIT and the occurrence of ICH is often difficult to predict. In this case, the infant presented with moderate thrombocytopenia and ICH, with subsequent permanent consequences.

Bleeding risk stratification in coronary artery surgery: the should-not-bleed score.

BACKGROUND: An estimated 20% of allogeneic blood transfusions in the United States are associated with cardiac surgery. It is estimated that 11% of red cell resources were used for transfusion support of patients undergoing coronary artery bypass grafting (CABG) with a documented wide variability in transfusion rate (7.8 to 92.8%). To address the issue of unnecessary transfusions within the CABG population, we developed a model to predict which patients are at low risk of bleeding for whom transfusion treatment might be considered unnecessary. Herein we present our "SHOULD-NOT-BLEED-SCORE" application developed for the Windows® software platform which is based on our previous research. METHODS: This study is aimed to develop a user-friendly application that stratifies patients with respect to bleeding risk. The statistical model we used in our previous research was focused on detection of CABG patients at low risk of bleeding. The rationale behind such an approach was to identify a CABG patient subgroup at low risk of bleeding. By identifying patients at low risk of bleeding we can define a subgroup of patients for whom transfusion treatment might be considered unnecessary. We developed a Windows platform application based on risk modelling which we previously calculated for 1426 patients undergoing elective CABG from January 2010 to January 2018. RESULTS: The SHOULD-NOT-BLEED-SCORE risk score is developed for the Windows software platform. A mathematical model that is based on multivariate analysis was used for app development. The variables that entered the scoring system were: Age; Body Mass Index; Chronic Renal Failure; Preoperative Clopidogrel Exposure; Preoperative Red Blood Cells Count; Preoperative Fibrinogen Level; Preoperative Multiplate ASPI test area under the curve (AUC) units. The SHOULD-NOT-BLEED-SCORE identifies/predicts patients without a risk for excessive bleeding with strong discriminatory performance (Receiver Operating Curve (ROC) analysis AUC 72.3%, p < 0.001). CONCLUSION: The SHOULD-NOT-BLEED risk scoring application may be useful in the preoperative risk screening process. The clinical and economic burden associated with unnecessary transfusions may be adequately addressed by a preoperative scoring system detecting patients at low risk of bleeding for whom transfusion treatment might be considered unnecessary.

Evaluation of the BD Stem Cell Enumeration Kit on the BD FACSCanto II flow cytometer using bd facscanto clinical and bd facsdiva software.

INTRODUCTION: CD34+ hematopoietic stem cell (HSC) enumeration by cell flow cytometry is routinely used in clinical laboratories for monitoring of HSC mobilization into peripheral blood and assessment of the quality of HSC products. The modified ISHAGE protocol is the most often used procedure for determination of CD34+ cells using flow cytometry. The aim of this study was to evaluate BD Enumeration stem cell kit on flow cytometer BD facscanto II, using facscanto clinical and facsdiva softwares. METHODS: Validation study included determination of within-run and between-run precision, trueness (bias), comparison of the test results analyzed on facscanto clinical and facsdiva softwares, assessment of linearity, specimen stability, and carryover. RESULTS: For between-run precision, coefficients of variation (CVs) were all <10%, except for low control level on facsdiva software. CVs for within-run precision were <10%, except for high absolute count of CD34+ cells on facsdiva software. Comparison of data showed no statistically significant differences between facscanto clinical and facsdiva software (Spearman's rank correlation coefficients were .993 for % of CD34+ cells and 0.983 for absolute count of CD34+ cells). In linearity study, bias for all dilutions was < 20%, and carryover assessment cannot be considered significant on both softwares. There was a statistically significant difference (P = .044) in absolute count of CD34+ cells after 24 hours of storage, when using facscanto clinical software. CONCLUSION: BD Stem Cell Enumeration Kit can be used in routine laboratory work on BD FACSCanto II instrument, whereas facscanto clinical and facsdiva software were used for acquisition and data analysis.

K antigens on neonatal red blood cells blocked by anti-K with titer of 32.

CONCLUSIONS: The blocking of red blood cell (RBC) antigens occurs when potent maternal antibodies bind to antigens on fetal or neonatal RBCs, causing them to be negative when typed with human IgM antisera. This phenomenon is rare; when it does occur, the antibody is usually of a high titer. This reported finding is typically due to anti-D, with rare reports describing false-negative K phenotyping due to blocking by maternal anti-K. We report a case of a potent anti-K with a titer of 32 that blocked K antigens on neonatal RBCs, causing them to phenotype as K-. The neonate also had clinically significant anemia (i.e., hemolytic disease of the newborn) due to the anti-K.

The Outcome of Hemolytic Disease of the Fetus and Newborn Caused by Anti-Rh17 Antibody: Analysis of Three Cases and Review of the Literature.

BACKGROUND: Anti-Rh17 is a rare red blood cell (RBC) antibody to high-frequency antigens that may cause severe hemolytic disease of the fetus and newborn (HDFN). Despite the rarity of HDFN caused by Anti-Rh17, this antibody was reported in many different populations. Emergency transfusions, especially exchange transfusions, present a huge problem if no compatible RBCs of phenotype D- are available. METHODS: Here we report obstetrical histories of three women and describe their pregnancies complicated by anti-Rh17 antibodies. We summarized published cases of pregnancies complicated by anti-Rh17 and reviewed transfusion treatment and outcomes. Additionally, a simplified flowchart for the management of such pregnancies is proposed. RESULTS: Four pregnancies were affected by severe HDFN, and three of them ended with perinatal death. In the fourth case, the baby was born hydropic and icteric and the condition was rapidly deteriorating. Emergency exchange transfusion was performed with incompatible O-negative RBC units in AB-negative plasma. The baby was discharged on the 14th day in good health. In the available literature, 15 women and 22 pregnancies were reported, 20 of them developed severe HDFN. According to the data, intrauterine transfusion for treatment of HDFN was the most common form of treatment with the donation of the mother's blood. Different options for exchange transfusion were described, including incompatible RBCs. CONCLUSION: In more than 90% of described pregnancies of HDFN caused by anti-Rh17 antibody, transfusion treatment was required. Therefore, RBC from D- phenotype has to be available. According to published data, in emergent circumstances when maternal and blood from donor with phenotype D- is not available, incompatible exchange transfusion is a better choice than delaying transfusion when it is necessary. It is of essential importance that pregnancies with high risk of HDFN due to anti-Rh17 are managed by a multidisciplinary team (transfusion medicine specialist, obstetrician, neonatologist) in a highly specialized tertiary institution.

Recurrent Aortic Infections Due to Unrecognized Aorto-Enteric Fistula.

We report a case of an infrarenal abdominal aortic aneurysm (AAA) with unrecognized primary aortoduodenal fistula (ADF), treated by endovascular aortic repair (EVAR). Endograft infection was diagnosed 12 months thereafter. The associated ADF was uncovered during open surgery, which included endograft extraction, in situ aortic reconstruction with a cryopreserved homograft (CHG) and duodenal repair. The patient was urgently reoperated in the early postoperative course, due to CHG rupture and subsequent hemorrhagic shock. After establishing control of hemorrhage, CHG was explanted, followed by aortic ligation and extraanatomical reconstruction with axillofemoral bypass. The importance of timely diagnosis of primary ADF prior to AAA repair, as well as treatment options and optimal materials for simultaneous aortic and bowel reconstruction in the setting of primary or secondary ADF, are discussed.

An automated mini buffy coat preparation method for use in mini extracorporeal photopheresis treatment of graft-vs-host-disease in a low body weight pediatric patient.

A mini extracorporeal photopheresis (mini-ECP) "off line" technique has been developed for use in the treatment of small children and patients with apheresis contraindications. Until now various methods have been used for buffy coat separation from whole blood. In this report we describe a protocol for mini buffy coat preparation using the automated Sepax laboratory separator for "off line" ECP treatment in a low body weight child with graft-vs-host-disease. According to our results this alternative method has been proven feasible and tolerable.

Susceptible and protective HLA-DR and HLA-DQ alleles for Fya alloimmunization in the Croatian population.

BACKGROUND: Alloimmunization is a known risk of transfusion therapy caused by exposure to foreign RBC antigens. However, alloimmunization is not observed in all transfused patients. Human leukocyte antigen (HLA) molecules may contribute to the recognition and presentation of foreign antigens and to the potency of immune responses that result in the production of antibodies. The aim of this study was to determine the association of HLA-DR and HLA-DQ polymorphisms with alloimunization to Fya antigen in Croatian patients. STUDY DESIGN AND METHODS: The study was conducted on 70 alloimmunized patients to Fya antigen and two control groups: 165 healthy Croatian individuals (Control 1) and 45 Fya antigen-negative nonimmunized patients exposed to Fya antigen (Control 2). Phenotype frequencies for HLA-DRB1 and HLA-DQB1 alleles were compared between the cases and control groups. RESULTS: Statistically significant differences in phenotype frequencies between cases and controls were found for DRB1*04 (odds ratios [ORs], 10.5 and 18.7 for Control 1 and Control 2, respectively), DRB1*15 (ORs, 8.0 and 6.9), and DQB1*02 alleles (ORs, 0.2 and 0.03); and DRB1*04-DQB1*03:01 (ORs, 7.9 and 17.6), DRB1*04-DQB1*03:02 (ORs, 5.5 and 7.6), DRB1*15-DQB1*06:02 (ORs, 7.3 and 5.5), DRB1*03-DQB1*02:01 (OR, 0.1), and DRB1*07-DQB1*02:02 (OR, 0.3) haplotypes. CONCLUSION: Several HLA-DRB1 and HLA-DQB1 alleles and haplotypes were proved to contribute to and protect from alloimmunization to Fya antigens. Alleles DRB1*04 and DRB1*15, as well as haplotypes DRB1*04-DQB1*03:02 and DRB1*15-DQB1*06:02 can be considered as risk factors, while allele DQB1*02 and haplotype DRB1*03-DQB1*02:01 have a protective role in Fya alloimmunization.

LEUKOCYTAPHERESIS IN THE MANAGEMENT OF SEVERE STEROID-DEPENDENT ULCERATIVE COLITIS.

Ulcerative colitis (UC) is a multifactorial disease of unknown precise etiology and immunopathogenesis. Peripheral blood granulocytes and monocytes/macrophages are the major sources of cytokines, which regulate inflammation. Leukocytapheresis (LCAP) is a method where blood is processed by apheresis system that removes lymphocytes and plasma before being returned to the body. We report the first case in Croatia where we used LCAP in the treatment of a patient with severe steroid-dependent UC. After 12 LCAP procedures, good clinical response was obtained and there were no significant adverse side effects noticed. The patient remained in clinical remission over two years in which he underwent regular follow ups at outpatient clinic. Over a 10-year follow-up period after LCAP, the patient had only occasional clinical symptoms of disease activity. The clinical course was complicated with the development of metastatic colorectal carcinoma, which points to the importance of regular disease monitoring rather than the increased risk of malignant disease after LCAP. Patients with UC are a demanding group of patients that warrant the search for novel treatment strategies other than conventional pharmacological therapies. Although LCAP is still not a common treatment modality in our daily practice, data from recent studies suggest it to be an effective and safe procedure in the management of active UC patients.

Comparative Analysis of Biological and Functional Properties of Bone Marrow Mesenchymal Stromal Cells Expanded in Media with Different Platelet Lysate Content.

Due to their ability to induce immunological tolerance in the recipient, mesenchymal stromal cells (MSCs) have been utilized in the treatment of various hematological and immune- and inflammation-mediated diseases. The clinical application of MSCs implies prior in vitro expansion that usually includes the use of fetal bovine serum (FBS). The present study evaluated the effect of different platelet lysate (PL) media content on the biological properties of MSCs. MSCs were isolated from the bone marrow of 13 healthy individuals and subsequently expanded in three different culture conditions (10% PL, 5% PL, 10% FBS) during 4 passages. The cells cultured in different conditions had comparable immunophenotype, clonogenic potential, and differentiation capacity. However, MSC growth was significantly enhanced in the presence of PL. Cultures supplemented with 10% PL had a higher number of cumulative population doublings in all passages when compared to the 5% PL condition (p < 0.03). Such a difference was also observed when 10% PL and 10% FBS conditions were compared (p < 0.005). A statistically significant difference in population doubling time was determined only between the 10% PL and 10% FBS conditions (p < 0.005). Furthermore, MSCs cultured in 10% PL were able to cause a 66.9% reduction of mitogen-induced lymphocyte proliferation. Three chromosome aberrations were detected in PL conditions. Since two changes occurred in the same do nor, it is possible they were donor dependent rather than caused by the culture condition. These findings demonstrate that a 10% PL condition enables a higher yield of MSCs within a shorter time without altering MSC properties, and should be favored over the 5% PL condition.

Autologous blood as a source of platelet gel for the effective and safe treatment of oral chronic graft-versus-host disease.

BACKGROUND: Oral chronic graft-versus-host disease (cGvHD) impairs oral function and patients' quality of life. Some lesions are refractory to local and systemic immunosuppressive therapy, and new therapeutic modalities are required. The aim of the study was to assess the efficacy and safety of topical application of autologous platelet gel (PG) in patients with oral cGvHD. STUDY DESIGN AND METHODS: PG was prepared from autologous blood and applied on ulcerous lesions using an automated system. The oral cGvHD was assessed using the 273-point Oral Mucositis Rating Scale (OMRS) prior and after completion of the PG treatment. The overall response to treatment of particular topography expressed as the total score on OMRS was compared to total score on National Institutes of Health cGvHD Oral Mucosal Score (NIH OMS). The pain intensity was measured by the Numeric Pain Rating Scale (NRS). RESULTS: In five patients, 12 autologous blood collections were performed; median 3 (range 1-3) per patient, and 26 PG applications were performed; median 6 (range 2-8) per patient. PG applications reduced lesions in oral cGvHD: median OMRS total score was reduced for 43.2% (range 9.6%-47.3%), and median NIH OMS total score for 27.3% (range 20.0%-50.0%) from baseline values. Median of pain intensity reduction on NRS scale was 57.1% (range 50%-100%). No side effects were observed. CONCLUSION: Application of autologous PG in oral cGvHD showed as an efficient and safe treatment option for patients who do not respond to standard local treatment.

Alloimmune neonatal neutropenia in Croatia during the 1998-2008 period.

PROBLEM: The aim of this study was to estimate the incidence of the disease and to analyze laboratory data of 23 newborns undergoing serologic testing for alloimmune neonatal neutropenia (ANN) during the 1998-2008 period in Croatia. METHOD OF STUDY: Laboratory data on 23 newborns undergoing serologic testing for ANN during the 1998-2008 period and epidemiologic data on the number of live births in Croatia were analyzed. Laboratory testing for ANN included serologic screening of maternal and neonatal sera and granulocytes (neutrophils) by immunofluorescence (IF) method. The monoclonal antibody immobilization of neutrophil antigens (MAINA) was employed to determine anti-HNA antibody specificity. RESULTS: Anti-HNA antibodies were detected in seven (54%) of 13 cases of serologically positive ANN. Only anti-HLA class I antibodies were demonstrated in four (31%) of 13 cases In the 2007-2008 period of prospective data collection, the number of serologically verified ANN cases was one case per 17,323 live births. Results of the prospective study conducted at Maternity Ward, Department of Gynecology and Obstetrics, Sestre milosrdnice University Hospital Center yielded the ANN incidence of one case per 2843 live births. CONCLUSION: Monitoring of neutrophil count in neonatal blood and serologic testing for ANN in case of isolated neutropenia in the newborn contributed considerably to timely detection of ANN. DESCRIPTORS: Neonatal alloimmune neutropenia-incidence, serologic diagnosis, antineutrophil antibodies, anti-HNA, anti-HLA class I, Croatia.

In situ repair of a mycotic suprarenal aortic aneurysm using a cryopreserved aortic homograft and visceral debranching in a patient with spondylodiscitis and left psoas muscle abscess.

We present a patient with ruptured suprarenal aortic aneurysm, involving origins of visceral and renal arteries. Associated spondylodiscitis and left psoas muscle abscess were also diagnosed. The patient was initially treated with antibiotics. Diagnostic survey showed progression of the aneurysm diameter and enlargement of the psoas muscle abscess. Surgical treatment using a cryopreserved aortic homograft with debranching of visceral arteries was performed. Different modalities of surgical repair within the infected aortic segment and the rationale for usage of cryopreserved homografts are considered. The importance of optimal timing for surgery is emphasized as well.

Two different dosing regimens of human recombinant erythropoietin beta during preoperative autologous blood donation in patients having hip arthroplasty.

PURPOSE: Our aim was to evaluate the effectiveness of two different dosing regimens of human recombinant erythropoietin (rHu-EPO) for preoperative autologous blood collection in patients undergoing total hip arthroplasty (THA). METHODS: Prospective randomised trials in which erythropoietin 15,000 IU was administered intravenously twice a week or 30,000 IU once a week (total 90,000 IU) combined with ferrous II sulphate (Ferro-Gradumet 2) orally and compared with Ferro-Gradumet 2 alone. RESULTS: Although different dosing regimens of rHu-EPO administration during preoperative autologous blood donation have similar effects on the collection of two units of autologous blood, preoperative haemoglobin level and perioperative allogenic blood transfusion, a once weekly dose regimen of rHu-EPO was more convenient (although not statistically significantly) for patients. CONCLUSION: We recommend the more practical and comfortable but yet highly effective therapeutic regimen with a single weekly intravenous administration of rHu-EPO for patients scheduled for THA.

[Croatian Society for Haematology and Transfusion Medicine Guidelines on the diagnosis and management of heparin induced thrombocytopenia (HIT)]. / Smjernice Hrvatskog drustva za hematologiju i transfuzijsku medicinu u dijagnosticko-terapijskom postupku za trombocitopeniju izazvanu heparinom (HIT).

Heparin induced thrombocytopenia (HIT) is a serious complication of heparin administration. In the last decade, this clinical syndrome has come into the focus of interest, primarily because of the severe thromboembolic complications that may lead to lethal outcome. In addition, great improvements have been made in the treatment with direct thrombin inhibitors and in laboratory diagnosis of HIT. As guidelines for diagnostic and management of HIT upgrade the quality of patient treatment, activities for their development have been launched in the Republic of Croatia. Based on British Committee for Standards in Haematology (BCSH) recommendations on diagnostic and treatment of HIT from 2006, activities for the introduction of new assays for anti-heparin antibodies were launched in 2008 and 2009, including algorithm of laboratory testing for HIT, sheet for clinical assessment of HIT (4T score), and education oftransfusiologists and clinicians. Upon evaluation of the results collected during one-year period, the Croatian Society of Haematology and Transfusion Medicine nominated a task force for the development of guidelines for HIT in January 2010. Following wide-ranging discussion, the guidelines were adopted in May 2011.