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No full international consensus exists on disease markers to be used for assessing the human iron status. Therefore this study was conducted to compare performances of serum ferritin and transferrin saturation (TSAT) versus soluble transferrin receptor (sTfR)/log ferritin and reticulocyte hemoglobin content (CHr), also known as Thomas-plot, in the diagnosis of iron deficiency (ID).A total of 445 consecutive hospitalized patients, referred for routine testing of the actual iron status, were included. Logistic regression models for the probability of functional ID (CHr28pg) were constructed for all 445 patients, for 225 patients without (C-reactive protein [CRP]≤0.5mg/dL) and 220 patients with acute-phase reaction (CRP0.5mg/dL).Based on the Thomas-plot analyses, 153/445 (34.38%) patients were identified with ID. When ID was diagnosed by means of serum ferritin levels30ng/mL and TSAT levels20%, 105/445 (23.60%) and 215/445 (48.31%) patients were identified with ID, respectively. The sTfR/log ferritin ratio showed the best positive predictive values (PPV) (62.50 and 64.41%) to indicate functional ID in patients without as well as with acute-phase reaction compared to sTfR (58.14 and 61.67%), ferritin (32.50 and 32.86%) and TSAT (26.74 and 42.86%).In clinical practice, the prevalence of ID and the accuracy to detect functional ID are dependent on marker selection and its definition. Regarding the results of this work, for laboratory investigation of ID, however, we suggest using Thomas-plot analyses in combination with ferritin single-marker measurements to efficiently identify patients with ID.

Background/Aims: While lactose malabsorption is a well-investigated condition, few epidemiologic data are available for fructose and sorbitol malabsorption. The aim of this study was to assess the prevalence rates for primary lactose malabsorption, fructose and sorbitol malabsorption, and carbohydrate-specific small intestinal bacterial overgrowth (cs-SIBO) in an Austrian outpatient center. Methods: In total, 306 adult patients, who were primarily referred with suspected carbohydrate malabsorption by general practitioners to our outpatient clinic, underwent genetic testing (C/T-13910 polymorphism) for primary lactose malabsorption, and a combined hydrogen (H2)/methane (CH4) breath test for fructose (25 g) and sorbitol (12.5 g) malabsorption. Cohen's kappa (κ) was calculated for agreement between positive breath test results and self-reported symptoms during the test. Results: Seventy-eight (25.49%) patients were C/C-13910 homozygotes, indicating primary lactose malabsorption. Thirty-four (11.11%) and 57 (18.63%) patients were classified as fructose and sorbitol malabsorbers. Cohen's κ measuring agreements between positive fructose and sorbitol breath test results and self-reported symptoms during the test were 0.33 and 0.49, respectively. Twenty-nine (9.50%) patients with an early H2/CH4 peak (i.e. within 60 minutes after fructose and/or sorbitol ingestion) were diagnosed with cs-SIBO. Conclusion: In Austria, carbohydrate malabsorption is a frequent condition in patients referred by general practitioners to carbohydrate malabsorption testing.