NEXT GENERATION OSMOTIC GRADIENT EKTACYTOMETRY FOR THE DIAGNOSIS OF HEREDITARY SPHEROCYTOSIS: METHOD VALIDATION AND FIRST DIAGNOSTIC EXPERIENCE OF TWO CENTERS
(Abstract release date: 05/19/16)
EHA Library. Lazarova E. 06/09/16; 133034; E1485
Dr. Elena Lazarova
Contributions
Contributions
Abstract
Abstract: E1485
Type: Eposter Presentation
Background
Osmotic gradient ektacytometry (Osmoscan) is part of the laboratory diagnosis process of hereditary spherocytosis (HS) and other red blood cell membrane disorders. A new generation ektacytometer, the LoRRca MaxSis, has recently become commercially available. We here present for the first time the experience of two independent institutions with this analyzer in HS diagnostic settings.
Aims
The objectives were (a) to validate the LoRRca MaxSis analytically independently in two centers, (b) to estimate the diagnostic accuracy of the various parameters available from the Osmoscan curve and their clinical application for HS diagnosis, (c) to establish a standardization of result reporting and cut-off values of Osmoscan parameters for HS diagnosis, and (d) to introduce the next generation osmotic gradient ektacytometry in the diagnostic work-flow of RBC membrane disorders.
Methods
Inter- and intra-assay variability and sample stability for different storage (4°C and 20°C) and anticoagulant conditions (K2-EDTA, Li-Heparin and acid-citrate-dextrose) were studied. In addition, we performed Osmoscan on samples from patients with HS (N=40), probable HS (N=21), auto-immune hemolytic anemia, AIHA (7), and patients with other pathologies (N=37). Daily control samples (n=54 in Erasme Hospital and n=80 in University Medical Center Utrecht) were run in parallel with patient samples. Laser-assisted measurements of RBC deformability under changing osmotic gradient and constant sheer stress were expressed and recorded as elongation index (EI). An Osmoscan curve was created with the following parameters: EI min (minimal elongation index), O min (the osmolality at EI min), EI max (the maximal elongation index), O max (the osmolality at EI max), O hyper (the osmolality in the hypertonic region at 50% of the EI max), EI hyper (the EI at O hyper), and area under the curve (AUC). Patient results for the various Osmoscan parameters were expressed as percent of change (increase or decrease) compared to the mean of controls.
Results
Analytical performance of the LoRRca MaxSis ektacytometer showed an inter-assay variability between 0.2% and 3%. Samples were stable for 48-72 hours depending on temperature storage and anticoagulant used. No difference was observed for any of the Osmoscan parameters between the “HS” group, “probable HS” and “AIHA” group. However, a significant difference was observed between the “HS” group and the “other pathologies” group for O min, EI max, EI hyper, and the AUC. The following diagnostic cut-offs were established for HS: an increase of more than 21.5 % for the osmolality point at the minimal elongation index (O min), a decrease of more than 8.5 % for the maximal elongation index (EI max), and a decreased area under the curve (AUC) of more than 18.5% compared to the mean of controls.
Conclusion
The next generation ektacytometer is an efficient tool for the laboratory diagnosis of HS. Samples are stable, thereby enabling long-distance shipping to specialized laboratories. Additionally, the proposed standardized reporting of results allows inter-laboratory exchange and comparison. Different parameters of the Osmoscan curve were found useful for HS diagnosis but particularly the AUC, the O min and the EI max parameters. Finally, we considered the introduction of the next generation ektacytometry Osmoscan in the diagnostic work-flow of RBC membrane disorders at two levels: (1) as a potent screening method in a general laboratory, and (2) as an effective intermediate step between the screening laboratory methods and the confirmatory protein deficiency tests or DNA-based methods in a reference laboratory.
Session topic: E-poster
Keyword(s): Diagnosis, Hereditary spherocytosis, Red blood cell
Type: Eposter Presentation
Background
Osmotic gradient ektacytometry (Osmoscan) is part of the laboratory diagnosis process of hereditary spherocytosis (HS) and other red blood cell membrane disorders. A new generation ektacytometer, the LoRRca MaxSis, has recently become commercially available. We here present for the first time the experience of two independent institutions with this analyzer in HS diagnostic settings.
Aims
The objectives were (a) to validate the LoRRca MaxSis analytically independently in two centers, (b) to estimate the diagnostic accuracy of the various parameters available from the Osmoscan curve and their clinical application for HS diagnosis, (c) to establish a standardization of result reporting and cut-off values of Osmoscan parameters for HS diagnosis, and (d) to introduce the next generation osmotic gradient ektacytometry in the diagnostic work-flow of RBC membrane disorders.
Methods
Inter- and intra-assay variability and sample stability for different storage (4°C and 20°C) and anticoagulant conditions (K2-EDTA, Li-Heparin and acid-citrate-dextrose) were studied. In addition, we performed Osmoscan on samples from patients with HS (N=40), probable HS (N=21), auto-immune hemolytic anemia, AIHA (7), and patients with other pathologies (N=37). Daily control samples (n=54 in Erasme Hospital and n=80 in University Medical Center Utrecht) were run in parallel with patient samples. Laser-assisted measurements of RBC deformability under changing osmotic gradient and constant sheer stress were expressed and recorded as elongation index (EI). An Osmoscan curve was created with the following parameters: EI min (minimal elongation index), O min (the osmolality at EI min), EI max (the maximal elongation index), O max (the osmolality at EI max), O hyper (the osmolality in the hypertonic region at 50% of the EI max), EI hyper (the EI at O hyper), and area under the curve (AUC). Patient results for the various Osmoscan parameters were expressed as percent of change (increase or decrease) compared to the mean of controls.
Results
Analytical performance of the LoRRca MaxSis ektacytometer showed an inter-assay variability between 0.2% and 3%. Samples were stable for 48-72 hours depending on temperature storage and anticoagulant used. No difference was observed for any of the Osmoscan parameters between the “HS” group, “probable HS” and “AIHA” group. However, a significant difference was observed between the “HS” group and the “other pathologies” group for O min, EI max, EI hyper, and the AUC. The following diagnostic cut-offs were established for HS: an increase of more than 21.5 % for the osmolality point at the minimal elongation index (O min), a decrease of more than 8.5 % for the maximal elongation index (EI max), and a decreased area under the curve (AUC) of more than 18.5% compared to the mean of controls.
Conclusion
The next generation ektacytometer is an efficient tool for the laboratory diagnosis of HS. Samples are stable, thereby enabling long-distance shipping to specialized laboratories. Additionally, the proposed standardized reporting of results allows inter-laboratory exchange and comparison. Different parameters of the Osmoscan curve were found useful for HS diagnosis but particularly the AUC, the O min and the EI max parameters. Finally, we considered the introduction of the next generation ektacytometry Osmoscan in the diagnostic work-flow of RBC membrane disorders at two levels: (1) as a potent screening method in a general laboratory, and (2) as an effective intermediate step between the screening laboratory methods and the confirmatory protein deficiency tests or DNA-based methods in a reference laboratory.
Session topic: E-poster
Keyword(s): Diagnosis, Hereditary spherocytosis, Red blood cell
Abstract: E1485
Type: Eposter Presentation
Background
Osmotic gradient ektacytometry (Osmoscan) is part of the laboratory diagnosis process of hereditary spherocytosis (HS) and other red blood cell membrane disorders. A new generation ektacytometer, the LoRRca MaxSis, has recently become commercially available. We here present for the first time the experience of two independent institutions with this analyzer in HS diagnostic settings.
Aims
The objectives were (a) to validate the LoRRca MaxSis analytically independently in two centers, (b) to estimate the diagnostic accuracy of the various parameters available from the Osmoscan curve and their clinical application for HS diagnosis, (c) to establish a standardization of result reporting and cut-off values of Osmoscan parameters for HS diagnosis, and (d) to introduce the next generation osmotic gradient ektacytometry in the diagnostic work-flow of RBC membrane disorders.
Methods
Inter- and intra-assay variability and sample stability for different storage (4°C and 20°C) and anticoagulant conditions (K2-EDTA, Li-Heparin and acid-citrate-dextrose) were studied. In addition, we performed Osmoscan on samples from patients with HS (N=40), probable HS (N=21), auto-immune hemolytic anemia, AIHA (7), and patients with other pathologies (N=37). Daily control samples (n=54 in Erasme Hospital and n=80 in University Medical Center Utrecht) were run in parallel with patient samples. Laser-assisted measurements of RBC deformability under changing osmotic gradient and constant sheer stress were expressed and recorded as elongation index (EI). An Osmoscan curve was created with the following parameters: EI min (minimal elongation index), O min (the osmolality at EI min), EI max (the maximal elongation index), O max (the osmolality at EI max), O hyper (the osmolality in the hypertonic region at 50% of the EI max), EI hyper (the EI at O hyper), and area under the curve (AUC). Patient results for the various Osmoscan parameters were expressed as percent of change (increase or decrease) compared to the mean of controls.
Results
Analytical performance of the LoRRca MaxSis ektacytometer showed an inter-assay variability between 0.2% and 3%. Samples were stable for 48-72 hours depending on temperature storage and anticoagulant used. No difference was observed for any of the Osmoscan parameters between the “HS” group, “probable HS” and “AIHA” group. However, a significant difference was observed between the “HS” group and the “other pathologies” group for O min, EI max, EI hyper, and the AUC. The following diagnostic cut-offs were established for HS: an increase of more than 21.5 % for the osmolality point at the minimal elongation index (O min), a decrease of more than 8.5 % for the maximal elongation index (EI max), and a decreased area under the curve (AUC) of more than 18.5% compared to the mean of controls.
Conclusion
The next generation ektacytometer is an efficient tool for the laboratory diagnosis of HS. Samples are stable, thereby enabling long-distance shipping to specialized laboratories. Additionally, the proposed standardized reporting of results allows inter-laboratory exchange and comparison. Different parameters of the Osmoscan curve were found useful for HS diagnosis but particularly the AUC, the O min and the EI max parameters. Finally, we considered the introduction of the next generation ektacytometry Osmoscan in the diagnostic work-flow of RBC membrane disorders at two levels: (1) as a potent screening method in a general laboratory, and (2) as an effective intermediate step between the screening laboratory methods and the confirmatory protein deficiency tests or DNA-based methods in a reference laboratory.
Session topic: E-poster
Keyword(s): Diagnosis, Hereditary spherocytosis, Red blood cell
Type: Eposter Presentation
Background
Osmotic gradient ektacytometry (Osmoscan) is part of the laboratory diagnosis process of hereditary spherocytosis (HS) and other red blood cell membrane disorders. A new generation ektacytometer, the LoRRca MaxSis, has recently become commercially available. We here present for the first time the experience of two independent institutions with this analyzer in HS diagnostic settings.
Aims
The objectives were (a) to validate the LoRRca MaxSis analytically independently in two centers, (b) to estimate the diagnostic accuracy of the various parameters available from the Osmoscan curve and their clinical application for HS diagnosis, (c) to establish a standardization of result reporting and cut-off values of Osmoscan parameters for HS diagnosis, and (d) to introduce the next generation osmotic gradient ektacytometry in the diagnostic work-flow of RBC membrane disorders.
Methods
Inter- and intra-assay variability and sample stability for different storage (4°C and 20°C) and anticoagulant conditions (K2-EDTA, Li-Heparin and acid-citrate-dextrose) were studied. In addition, we performed Osmoscan on samples from patients with HS (N=40), probable HS (N=21), auto-immune hemolytic anemia, AIHA (7), and patients with other pathologies (N=37). Daily control samples (n=54 in Erasme Hospital and n=80 in University Medical Center Utrecht) were run in parallel with patient samples. Laser-assisted measurements of RBC deformability under changing osmotic gradient and constant sheer stress were expressed and recorded as elongation index (EI). An Osmoscan curve was created with the following parameters: EI min (minimal elongation index), O min (the osmolality at EI min), EI max (the maximal elongation index), O max (the osmolality at EI max), O hyper (the osmolality in the hypertonic region at 50% of the EI max), EI hyper (the EI at O hyper), and area under the curve (AUC). Patient results for the various Osmoscan parameters were expressed as percent of change (increase or decrease) compared to the mean of controls.
Results
Analytical performance of the LoRRca MaxSis ektacytometer showed an inter-assay variability between 0.2% and 3%. Samples were stable for 48-72 hours depending on temperature storage and anticoagulant used. No difference was observed for any of the Osmoscan parameters between the “HS” group, “probable HS” and “AIHA” group. However, a significant difference was observed between the “HS” group and the “other pathologies” group for O min, EI max, EI hyper, and the AUC. The following diagnostic cut-offs were established for HS: an increase of more than 21.5 % for the osmolality point at the minimal elongation index (O min), a decrease of more than 8.5 % for the maximal elongation index (EI max), and a decreased area under the curve (AUC) of more than 18.5% compared to the mean of controls.
Conclusion
The next generation ektacytometer is an efficient tool for the laboratory diagnosis of HS. Samples are stable, thereby enabling long-distance shipping to specialized laboratories. Additionally, the proposed standardized reporting of results allows inter-laboratory exchange and comparison. Different parameters of the Osmoscan curve were found useful for HS diagnosis but particularly the AUC, the O min and the EI max parameters. Finally, we considered the introduction of the next generation ektacytometry Osmoscan in the diagnostic work-flow of RBC membrane disorders at two levels: (1) as a potent screening method in a general laboratory, and (2) as an effective intermediate step between the screening laboratory methods and the confirmatory protein deficiency tests or DNA-based methods in a reference laboratory.
Session topic: E-poster
Keyword(s): Diagnosis, Hereditary spherocytosis, Red blood cell
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