Clinical view versus guideline adherence in ferritin monitoring and initiating iron chelation therapy in patients with myelodysplastic syndromes.

OBJECTIVES: In patients with myelodysplastic syndromes (MDS) with >20 transfusions and ferritin levels >1000 µg/L, international guidelines recommend iron chelation therapy (ICT). The study's objective was to determine guideline adherence and the intensity of ferritin monitoring in clinical practice. METHODS: We performed an observational population-based study using the HemoBase Registry, which contains data of all MDS patients diagnosed since 2005 in Friesland, the Netherlands. Clinical information on transfusions, ferritin measurements, ICT, and clinical performance as defined by age ≤ 80 years, Charlson Comorbidity Index <2 and lower-risk MDS was collected from health records. RESULTS: Two hundred and thirty seven of 292 patients (81.1%) received ≥1 transfusion, and 121 (41.4%) received >20 transfusions. In 57 of these 121 patients (47.1%), ferritin measurements were performed at least once. Clinical performance was significantly associated with monitoring ferritin around the 20th transfusion (RR: 2.49, p = .016). Clinical performance was also associated with initiating ICT (RR: 5.99, p < .001). ICT was offered to 22.3% (n = 25) of eligible patients. CONCLUSIONS: In this population-based study, ferritin levels were measured in <50% of MDS patients who received >20 transfusions, and clinical performance was significantly associated with measuring ferritin. Our study suggests that in heavily transfused MDS patients, ferritin monitoring is primarily based on patients' clinical performance rather than guideline recommendations.

Flow cytometric mepacrine fluorescence can be used for the exclusion of platelet dense granule deficiency.

BACKGROUND: δ-storage pool disease (δ-SPD) is a bleeding disorder characterized by a reduced number of platelet-dense granules. The diagnosis of δ-SPD depends on the measurement of platelet ADP content, but this test is time consuming and requires a relatively large blood volume. Flow cytometric analysis of platelet mepacrine uptake is a potential alternative, but this approach lacks validation, which precludes its use in a diagnostic setting. OBJECTIVES: To evaluate the performance of platelet mepacrine uptake as a diagnostic test for δ-SPD. PATIENTS/METHODS: Mepacrine fluorescence was determined with flow cytometry before and after platelet activation in 156 patients with a suspected platelet function disorder and compared with platelet ADP content as a reference test. Performance was analyzed with a receiver operating characteristic (ROC) curve. RESULTS: Eleven of 156 patients had δ-SPD based on platelet ADP content. Mepacrine fluorescence was inferior to platelet ADP content in identifying patients with δ-SPD, but both mepacrine uptake (area under the ROC curve [AUC] 0.87) and mepacrine release after platelet activation (AUC 0.80) had good discriminative ability. In our tertiary reference center, mepacrine uptake showed high negative predicitive value (97%) with low positive predictive value (35%). Combined with a negative likelihood ratio of 0.1, these data indicate that mepacrine uptake can be used to exclude δ-SPD in patients with a bleeding tendency. CONCLUSION: Mepacrine fluorescence can be used as a screening tool to exclude δ-SPD in a large number of patients with a suspected platelet function disorder.

Toward Flow Cytometry Based Platelet Function Diagnostics.

The laboratory diagnostics of (inherited) platelet function disorders mainly comprises aggregation and secretion assays, which may be suitable for diagnosing some specific severe platelet function disorders, but are not reliable enough for diagnosing mild platelet function disorders or disorders associated with low platelet count. Flow cytometric assessment of platelet reactivity will expectedly provide additional value during the diagnostic work-up of platelet function disorders because it only requires a small volume of whole blood and allows the measurement of platelet function in thrombocytopenic samples. Flow cytometry has frequently been used to evaluate platelet function in the research setting, and therefore, these assays will require clinical validation before they can be used as routine diagnostic tools. The main challenge in the validation of innovative platelet function diagnostic tests is the lack of a gold standard test for mild platelet function disorders. This review aims to address the many applications of flow cytometry in the current diagnostic work-up of platelet function testing and to discuss the challenges in introducing new tools for diagnosing platelet function disorders.