Inappropriate calibration and optimisation of pan-keratin (pan-CK) and low molecular weight keratin (LMWCK) immunohistochemistry tests: Canadian Immunohistochemistry Quality Control (CIQC) experience

2011 ◽  
Vol 64 (3) ◽  
pp. 220-225 ◽  
Author(s):  
Maria Copete ◽  
John Garratt ◽  
Blake Gilks ◽  
Dragana Pilavdzic ◽  
Richard Berendt ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Quality Control ◽  
Proficiency Testing ◽  
False Negative ◽  
Great Majority ◽  
Epithelial Differentiation ◽  
Low Molecular Weight ◽  
Reference Laboratory ◽  
Selection Of ◽  
Positive Controls

AimsPan-cytokeratin (pan-CK) and low molecular weight cytokeratin (LMWCK) tests are the most common immunohistochemistry (IHC) tests used to support evidence of epithelial differentiation. Canadian Immunohistochemistry Quality Control (CIQC), a new provider of proficiency testing for Canadian clinical IHC laboratories, has evaluated the performance of Canadian IHC laboratories in two proficiency testing challenges for both pan-CK and LMWCK.MethodsCIQC has designed a 70-sample tissue microarray (TMA) for challenge 1 and a 30-sample TMA for challenge 2. There were 13 participants in challenge 1, and 62 in challenge 2. All results were evaluated and scored by CIQC assessors and compared with reference laboratory results.ResultsParticipating laboratories often produced false-negative results that ranged from 20% to 80%. False-positive results were also detected. About half of participating clinical laboratories have inappropriately calibrated IHC tests for pan-CK and LMWCK, which are the most commonly used markers for demonstration of epithelial differentiation. The great majority of laboratories were not aware of the problem with calibration of pan-CK and LMWCK tests because of inappropriate selection of external positive controls and samples for optimisation of these tests. Benign liver and kidney are the most important tissues to include as positive controls for both pan-CK and LMWCK.ConclusionsParticipation in external quality assurance is important for peer comparison and proper calibration of IHC tests, which is also helpful for appropriate selection of positive control material and material for optimisation of the tests.

scholarly journals Selection of inorganic-based fertilizers in forward osmosis for water desalination

2015 ◽  
Vol 4 (2) ◽  
pp. 319-329 ◽  
Author(s):  
Tripti Mishra ◽  
RK Srivastava
Keyword(s):  
Molecular Weight ◽  
Water Flux ◽  
Forward Osmosis ◽  
Direct Application ◽  
Water Desalination ◽  
Performance Ratio ◽  
Low Molecular Weight ◽  
Inorganic Fertilizers ◽  
The Difference ◽  
Selection Of

The current study aims at the selection of an appropriate draw solute for forward osmosis process. Separation and recovery of the draw solute are the major criteria for the selection of draw solute for forward osmosis process. Therefore in this investigation six inorganic fertilizers draws solute were selected. The selections of inorganic fertilizers as draw solute eliminate the need of removal and recovery of draw solute from the final product. The final product water of forward osmosis process has direct application in agricultural as nutrient rich water for irrigation. These inorganic fertilizers were tested based on their water extraction (water flux) capacity. This experimental water flux was compared with the observed water flux. It was noted that the observed water flux is much higher than the attained experimental water flux. The difference of these two fluxes was used to calculate the performance ratio of each selected fertilizer. Highest performance ratio was shown by low molecular weight compound ammonium nitrate (22.73) and potassium chloride (21.03) at 1 M concentration, whereas diammonium phosphate (DAP) which has highest molecular weight among all the selected fertilizer show the lowest performance ratio (10.02) at 2 M concentration. DOI: http://dx.doi.org/10.3126/ije.v4i2.12660 International Journal of Environment Vol.4(2) 2015: 319-329

Charts of operational process specifications ("OPSpecs charts") for assessing the precision, accuracy, and quality control needed to satisfy proficiency testing performance criteria

1992 ◽  
Vol 38 (7) ◽  
pp. 1226-1233 ◽  
Author(s):  
J O Westgard
Keyword(s):  
Quality Control ◽  
Proficiency Testing ◽  
Measurement Procedure ◽  
Performance Criteria ◽  
Operating Point ◽  
Operational Process ◽  
Testing Performance ◽  
Analytical Errors ◽  
Current Operating ◽  
Selection Of

Abstract “Operational process specifications” have been derived from an analytical quality-planning model to assess the precision, accuracy, and quality control (QC) needed to satisfy Proficiency Testing (PT) criteria. These routine operating specifications are presented in the form of an “OPSpecs chart,” which describes the operational limits for imprecision and inaccuracy when a desired level of quality assurance is provided by a specific QC procedure. OPSpecs charts can be used to compare the operational limits for different QC procedures and to select a QC procedure that is appropriate for the precision and accuracy of a specific measurement procedure. To select a QC procedure, one plots the inaccuracy and imprecision observed for a measurement procedure on the OPSpecs chart to define the current operating point, which is then compared with the operational limits of candidate QC procedures. Any QC procedure whose operational limits are greater than the measurement procedure's operating point will provide a known assurance, with the percent chance specified by the OPSpecs chart, that critical analytical errors will be detected. OPSpecs charts for a 10% PT criterion are presented to illustrate the selection of QC procedures for measurement procedures with different amounts of imprecision and inaccuracy. Normalized OPSpecs charts are presented to permit a more general assessment of the analytical performance required with commonly used QC procedures.

scholarly journals Instrumentation for Routine Analysis of Acrylamide in French Fries: Assessing Limitations for Adoption

Foods ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2038
Author(s):  
Mark M. Skinner ◽  
Jared T. Seale ◽  
Maranda S. Cantrell ◽  
Joseph M. Collins ◽  
Matthew W. Turner ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Quality Control ◽  
Measurement Method ◽  
Process Industry ◽  
French Fries ◽  
Low Molecular Weight ◽  
Oil Degradation ◽  
Trained Personnel ◽  
Pros And Cons ◽  
Low Levels

The purpose of this experimental review was to detect acrylamide in French fries using methods most adaptable to the food process industry for quality control assessment of products. French fries were prepared at different cook times using the same fryer oil over a five-day period to assess the influence of oil degradation and monitor trends in acrylamide formation. Acrylamide detection was performed using LC-MS, GC-MS and FT-NIR. The low levels of acrylamide produced during frying, low molecular weight of the analyte, and complexity of the potato matrix make routine acrylamide measurement challenging in a well-outfitted analytical lab with trained personnel. The findings of this study are presented from the perspective of pros and cons of each acrylamide measurement method in enough detail for food processors to appraise the method that may work best for them based on their available instrumentation and extent of personnel training.

Anti Xa Monitoring during Treatment with Low Molecular Weight Heparin or Danaparoid: Inter-assay Variability

1999 ◽  
Vol 82 (10) ◽  
pp. 1289-1293 ◽  
Author(s):  
R. Iampietro ◽  
A. M. Woolley ◽  
F. E. Preston ◽  
S. Kitchen
Keyword(s):  
Molecular Weight ◽  
Therapeutic Range ◽  
Low Molecular Weight Heparin ◽  
Assay Method ◽  
Target Range ◽  
Low Molecular Weight ◽  
The Mean ◽  
The Relationship ◽  
Higher Doses ◽  
Selection Of

SummaryIf laboratory monitoring of low molecular weight heparin (LMWH) therapy is required the test of choice is the anti Xa activity assay. The relationship between anti Xa results obtained using different techniques is unknown. The aim of the present study was to compare anti Xa results obtained with eight different commercially available anti Xa activity assays (five chromogenic and three clotting based assays) in samples from patients receiving either therapeutic or prophylactic LMWH (enoxaparin or dalteparin) or danaparoid.We have demonstrated that highly significant differences exist between results obtained using different techniques. The mean anti Xa activity in patients receiving treatment or prophylaxis with enoxaparin ranged from 0.28 to 0.64 iu/ml. A similar relationship was present in samples from patients treated with dalteparin, mean anti Xa results ranging from 0.43 to 0.69 iu/ml. The Heptest clotting assay as used here in combination with the Automated Coagulation Laboratory instrument, was associated with lower results than other clotting or chromogenic techniques. In patients receiving danaparoid for heparin induced thrombocytopaenia (HIT) mean results with three clotting based assays were 0.30 to 0.36 u/ml, compared to mean results of 0.47 to 0.65 u/ml for chromogenic assays.Our data clearly indicate that the selection of anti Xa assay method could influence patient management since the dose required to achieve the therapeutic range would differ according to the assay employed. This is particularly important since the frequency of hamorrhagic side effects has been shown by others to be dose dependant, irrespective of the concomitant anti Xa activity results. In danaparoid therapy the clotting assays studied here should not be employed for monitoring without a modified target range, unless it can be demonstrated that the higher doses required to achieve the therapeutic range are safe.

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