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It is common practice in laboratories to store biological samples in ultra-low temperature (ULT) freezers. There is growing interest in raising the temperature of ULT freezers in order to save energy and reduce expenses, as energy conservation becomes increasingly important and sustainable laboratory practices gain popularity. In our laboratory, plasma samples are stored for three months for diagnostic purposes. We therefore took the opportunity to investigate the effect of two different storage temperatures (−70 °C vs −80 °C), on activated partial thromboplastin time (APTT), factor VIII (FVIII), international normalized ratio (INR) and factor VII (FVII) measurements on paired plasma samples collected from 26 individuals after three months of storage. Automated coagulation analysers CS-5100 and ACL TOP were used to perform the tests. We found no consistent difference between the two storage temperatures for any of the four coagulation parameters (all p-values > 0.05). We conclude that the temperature of ULT freezers used to store plasma samples for APTT, FVIII, INR, and FVII measurements can be safely increased from −80 to −70 °C without affecting the stability of the samples. [ABSTRACT FROM AUTHOR]

This letter to the editor discusses the challenges of diagnosing platelet disorders and presents a case study of a patient with a δ-granule storage pool disease. The patient had a history of bleeding symptoms and was diagnosed using flow cytometry analysis of CD63 expression on activated platelets and liquid chromatography tandem mass spectrometry (LC-MS/MS) measurement of plasma serotonin release after platelet activation. The study suggests that these methods may be reliable for diagnosing δ-granule defects in laboratories with the necessary equipment. The authors emphasize the importance of using multiple methods for accurate diagnosis and highlight the limitations of light transmission aggregometry (LTA) in detecting δ-granule defects. [Extracted from the article]

Patients undergoing coronary artery bypass graft (CABG) surgery or carotid endarterectomy (CEA) continue antiplatelet therapy perioperatively, which may increase bleeding risk. We aimed to investigate whether Rotational thromboelastometry (ROTEM®) platelet, a newly marketed platelet function analysis, would detect antiplatelet therapy in CABG and CEA patients; whether detection of reduced platelet function was associated with increased bleeding; and whether ex vivo desmopressin increased platelet function. We included 20 CABG patients continuing aspirin and 20 CEA patients continuing clopidogrel (n = 1) or clopidogrel and aspirin (n = 19). Platelet function was analyzed with ROTEM®platelet and light transmission aggregometry (LTA). According to the lower reference limit, ROTEM®platelet managed to detect aspirin, but clopidogrel detection was inadequate compared to LTA. Using a previously published cut-off for bleeding risk, 6 (30%) patients receiving aspirin and 4 (21%) patients receiving both clopidogrel and aspirin demonstrated platelet function below this cut-off. One of the four CEA patients below the cut-off died from intracerebral hemorrhage postoperatively. CABG patients below (n = 6) and above (n = 14) the cut-off did not differ in chest tube output (median [range]: 373 ml [250–900] vs. 368 ml [195–820]). Ex vivo addition of desmopressin did not increase platelet function. In conclusion, ROTEM®platelet does reveal aspirin treatment whereas clopidogrel treatment is most often overlooked. Due to low bleeding in the study population, it was not possible to conclude on the association with bleeding risk. [ABSTRACT FROM AUTHOR]

Lactase persistence and thereby tolerance to lactose is a common trait in people of Northern European descent. It is linked to the LCT −13910C>T variant located in intron 13 of the MCM6 gene 13.9 kb upstream of the lactase ( LCT) gene. In people of African and Middle Eastern descent, lactase persistence can be associated with other variants nearby the −13910C>T variant, limiting the use of the −13910C>T-based SNP analysis, e.g. TaqMan assays for the diagnosis of lactose intolerance. Using high-resolution melting analysis, we identified five samples that were heterozygous for the −13915T>G variant among 78 patients genotyped as −13910C/C by a TaqMan assay. All samples originated from patients of probable Middle Eastern descent. In order to detect the −13910 and −13915 variants simultaneously, we developed a new high-resolution melting (HRM) analysis assay based on unlabeled probe genotyping and simultaneous amplicon scanning analysis. By using this assay we were able to distinguish the −13910 and −13915 genotypes clearly. Furthermore, we identified two rare variants, the −13907C>G and −13913T>C. With this method, based on an inexpensive unlabeled probe, it is possible to simultaneously detect the −13910C>T and −13915T>G variants in addition to rarer variants surrounding the −13910 site. This new method may contribute to improve the diagnostic performance of the genetic analysis for lactose intolerance. [ABSTRACT FROM AUTHOR]