The post-analytical phase is the final phase of the total testing process and involves evaluation of laboratory test results; release of test results in a timely manner to appropriate individuals, particularly critical results; and modification, annotation or revocation of results as necessary to support clinical decision-making. Here we present a series of recommendations for post-analytical best practices, tailored to medical biochemistry laboratories in Croatia, which are intended to ensure alignment with national and international norms and guidelines. Implementation of the national recommendations is illustrated through several examples.

In Croatian medical laboratories (ML), external quality assessment (EQA) has a long tradition of almost half of a century. At national level, EQA is provided by Croatian Centre for Quality Assessment in Laboratory Medicine (CROQALM) which is a part of Croatian Society of Medical Biochemistry and Laboratory Medicine.
This case study aimed to summarize the main challenges, which are set to CROQALM and their possible solutions.
CROQALM has 10 schemes, covering majority of analysis for which medical biochemistry laboratories in Croatia are authorized for, including pre-analytical and post-analytical phase of laboratory work. Assessment scheme has three exercises per year. One sample per scheme and exercise is distributed to participants depending on their application. All data transfer and evaluation of the results are done using web interface and statistical software for evaluation of quality in laboratory medicine.
Since CROQALM has relatively small number of participating laboratories (N = 197) with lot of different manufacturers of instruments used for analysis in all schemes, constant challenges are present in the evaluation of the results (commutability problems, statistical analysis etc.). Further, number of participating medical laboratories is even lower for highly specific parameters, which are in the scope of clinical laboratories only.
Despite the obstacles we are faced to, EQA at national level is useful tool regarding standardization and harmonization aspects in total testing process within the country. Furthermore, it gives participating laboratories recognition and proof for meeting expected quality criteria in the community they serve.

e15551 Background: Gastric cancer (GC) is the 8th most common cancer cause of cancer deaths in Croatia and 2nd most common cause of cancer deaths worldwide. GC of the intestinal type is usually preceded by a chronic atrophic gastritis which is a precancerous change in the stomach. Methods: A reliable diagnostic tool for the early detection of the GC is essential. Screening programs have led to an improvement of overall 5-y survival rate for GC in Japan and Pepsinogen test method was suggested to reduce mortality from gastric cancer. The gold standard for the diagnosis of GC is the pathohistological study of biopsies obtained during an upper GI endoscopy, an invasive method that is too complicated for use in population screening and patients with comorbidity. We have conducted a prospective single center clinical study over a period of > 2 years to evaluate sensitivity and specificity of reagents, and to determine if these reagents can be part of routine. Inclusion criteria for the study were: signed informed consent, life expectancy > 12, and exclusion criteria were: previous treatments for any malignancy, current usage of IPP or NSAIDs medication, poor ECOG performance status ≥3, known history of H. pylori eradication treatment or gastric surgery. We previously reported preliminary results of PG test method in Croatian population. Here, we present mature data after median follow-up of 26 months. Statistical analyses were performed by using a Mann-Whitney U test, multiple logistic regression and the receiver operating characteristics (ROC) to evaluate the predictive power of biomarkers. Results: Blood samples have been collected from patients with suspicious to GC attending for endoscopy or surgery. We used cut off points to evaluate gastric cancer risk: PGI ≤ 70 and PGI/II ratio ≤ 3.0. Of the 116 patients, 25 patients had GC and 91 had non-malignant pathology on tissue biopsy (like atrophic gastritis). Based on an optimal cut-off value calculated by ROC curve analysis had accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of 86.2%, 60.0%, 93.4%, 65.2%and 89.47%, respectively, for the diagnosis of GC. AUC was 0.767 (95% CI 64.0-89.0). Conclusions: The single use of pepsinogen tests is not sufficient for stomach cancer detection; however, it provides a valuable test for selecting a population that needs further diagnosing. Meanwhile, its high specificity could also help to avoid unnecessary endoscopy, especially in older population or patients with heavy burden of comorbidity. Clinical trial information: 2016-0019-34.

Background: Gastric cancer (GC) is the eighth most common cause of cancer deaths in Croatia and one of the most common causes of cancer deaths worldwide. A reliable diagnostic tool for the early detection of GC is essential. Objective: We previously suggested a pepsinogen test method to reduce the mortality from GC by allowing early detection. Here, we report an updated analysis from a prospective single-center clinical study to evaluate the sensitivity and specificity of the pepsinogen test method and to determine whether this test can be used as a part of routine laboratory assessment of high-risk patients. Methods: We present mature data of the pepsinogen test method in the Croatian population after a median follow-up of 36 months. Statistical analyses were performed using a Mann-Whitney U test, multiple logistic regression, and receiver operating characteristics (ROC) to evaluate the predictive power of the assayed biomarkers. Results: Of the 116 patients, 25 patients had GC and 91 demonstrated a nonmalignant pathology based on tissue biopsy. Cutoff values were pepsinogen I ⩽70 and pepsinogen I/II ratio ⩽3.0. Using ROC curve analysis, the accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were determined to be 87.22%, 78.12%, 90.10%, 71.43%, and 92.86%, respectively, for the diagnosis of GC. The area under the curve was 0.700 (95% confidence interval 0.57–0.83). Conclusion: Pepsinogen tests are valuable for screening a population in need of further diagnosis and could help to avoid unnecessary invasive endoscopic procedures.

Introduction: Autovalidation (AV) is an algorithm based on predefined rules designed, among others, to automate and standardize the postanalytical phase of laboratory work. The aim of this study was to examine the overall opinion of Croatian medical biochemistry laboratories regarding various aspects of AV. Material and methods: This retrospective study is an analysis of the responses of a survey about AV comprised of 18 questions, as part of Module 10 (“Postanalytical phase of laboratory testing”) of national External Quality Assessment program, administered by the Croatian Centre for Quality Assessment in Laboratory Medicine. Results were reported as percentages of total number of participants in survey or as proportions of observed data if the overall number of data was <100. Results: 121 laboratories responded to the survey, of which 76% do not use AV, while 11% of laboratories use AV in routine laboratory work. 16/29 laboratories implemented semi-automated AV for general biochemistry (7/29), haematology (5/29), and coagulation (4/29) tests. Analytical measurement ranges, critical values, flags from analysers, interference indices and delta check were the most commonly used rules in the algorithm. 12/29 laboratories performed validation of AV with less than 500 samples (8/29). 7/13 laboratories report the percentage of AV being 20-50%, while 10/13 answered that introduction of AV significantly reduced turnaround time (TAT) (for 20 - 25%), especially for biochemistry tests. Conclusions: Despite of its numerous benefits (i.e. shorter TAT, less manual validation, standardization of the postanalytical phase), only a small number of Croatian laboratories use AV.