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Do diet restrictions reduce the number of positive results for the fecal occult blood test?
1180
Abstracts
Results: The upper limit of the reference intervals of the different age groups is shown in Table 1. Though the sample collection was evenly distributed among the seasons, we did not observe a seasonal effect (F = 0.84, p = 0.47). Table 1 Upper limit of normal of Antistreptolysin O titer calculated by the Robust method (CLSI C28-A3). Age group
N (%males)
Outliers Tukey's method
ASO-ULN
90% Confidence interval
≤ 5 years
28 (57%)
3
216.74 IU/ml
14 3
539.10 IU/ml 340.50 IU/ml
164.71 to 268.77 Derived by Bootstrap resampling 495.97 to 581.06 289.26 to 409.15
6 to 15 years 192 (50%) ≥ 16 years 50 (42%)
Conclusions: The highest ASO titers were seen in children between the ages of 6 and 15 years. doi:10.1016/j.clinbiochem.2011.06.055
P545 Do diet restrictions reduce the number of positive results for the fecal occult blood test? R. Bunyan, K.L. Schnabl, T.N. Higgins, L. Denesiuk DynaLIFEDx, #200, 10150–102 St, Edmonton, Alberta, T5J 5E2, Canada Objective: Fecal occult blood test (FOBT) screening has been shown to decrease the incidence and mortality from colorectal cancer. To increase public awareness and to encourage patient compliance, a provincial campaign was launched and dietary restrictions for fecal occult blood testing in Alberta were removed on January 19, 2009. Methods: Subjects refrained from vitamin C supplementation and specimens were kept at room temperature for 72 h to remove peroxidases prior to performing the FOBT by the guaiac method. Data for the FOBT before and after the abolition of dietary restrictions was extracted from the laboratory information system. The positivity rate for the FOBT in urban and rural populations was compared. Results: Physicians reported an increase in the absolute number of positive results leading to an increased number of colonoscopies. For the year prior to abolition of dietary restrictions, the positivity rate in Edmonton and the rural communities was 1.80% and 1.79%, respectively; whereas for the year after it was 1.71% and 1.76%. The number of samples tested increased by almost 100% from January 2008 to December 2010. Conclusions: The removal of dietary restrictions dramatically improved patient compliance, had no significant impact on the positivity rate, and markedly reduced the number of telephone calls to the clinical chemists regarding clarification of dietary restrictions. The simultaneous change to the laboratory methods reduced interference from dietary peroxidases. doi:10.1016/j.clinbiochem.2011.06.056
P546 Validation of an enzyme immunoassay (EIA) for quantification of free testosterone (fTE) in serum J.L.V. Shaw a,b, L. Grossi c, I.M. Blasutig a,b, P.M. Yip a,b a Laboratory Medicine Program, University Health Network, Toronto, Ontario, Canada b Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada c Inter Medico, Markham, Ontario, Canada
Objective: To evaluate the Diagnostic Biochem Canada (London, ON) EIA method for the measurement of serum free testosterone (fTE). Methods: Imprecision was determined by measurement of BioRad Immunoassay Plus quality control material using two reagent lots over four plates. Linearity was assessed using six levels of calibrator material, measured in duplicate. The claimed EIA sensitivity was verified by measurement of the zero calibrator. Patient serum samples (n = 60) sent to Toronto General Hospital for fTE measurement were used for method comparison against the established RIA method (Siemens DPC). EIA analyses were performed in duplicate and compared to the RIA results using linear regression analysis. Reference interval studies were performed using samples from apparently healthy individuals (n = 23 male; n = 23 female). Antibodies used in both the EIA and RIA methods are specific for free testosterone and the assay procedures have been optimized to maintain the existing equilibrium between bound and free testosterone in patient serum. Results: The EIA method showed acceptable imprecision with CVs less than 10% for low (4 pmol/L; 9.5%), medium (25 pmol/L; 5.2%) and high (100 pmol/L; 7.3%) fTE levels of QC material. The EIA method was linear within the stated analytical measuring range of 0.9-433 pmol/L and agreed with the manufacturer's claimed limit of detection. Linear regression analysis identified the relationship between RIA(x) and EIA(y) measurements as: y = 1.037x − 5.97. The correlation coefficient for the two methods was 0.757. The stated reference range for fTE in females was verified, however further studies are needed for males due to several values which fell below the stated range. Conclusions: The fTE EIA demonstrated acceptable performance and produced results comparable to those made by RIA, although the local reference interval for males may be lower than stated. doi:10.1016/j.clinbiochem.2011.06.057
P547 Comparision of hemoglobin A1c (HbAIc) measurement in whole blood vs measurement in blood extracted from dried blood spots (DBS) using the tina-quant hemoglobin A1c GEN. 2 method on the cobas integra 400 plus analyzer J.L.V. Shaw a,b, D. Konforte a,b, B. Hoffman a,b, A. Azad a a Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada b Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada Objectives: To optimize HbA1c measurement from DBS on the Cobas Integra 400 analyzer and to compare HbA1c results obtained from DBS with those from whole blood. Methods: The optimal number of 3 mm punched discs and extraction time required to apply the Hemolysate Application of the Tina-quant Gen 2 method on the Cobas Intergra 400 to the measurement of HbA1c from DBS was determined. DBS were prepared from EDTA-anticoagulated blood samples (n = 48) sent for routine measurement of HbA1c. HbA1c measurements from DBS were compared (EP5-A2 CLSI) to HbA1c measured from the corresponding whole blood by the Cobas Integra Whole Blood Application protocol of the Tina-quant Gen 2 method. DBS with high (0.095), medium (0.063) and low (0.048) levels of HbA1c were used to determine imprecision (20 days). Linearity was assessed over a range of hematocrits and haemoglobin concentrations. Results: Three 3 mm DBS incubated in 500μL of hemolysis reagent for 3 hours was optimal. Comparison between DBS (y) and whole blood (x) HbA1c gave y = 0.94x + 0.36; R 2 0.99. The DBS method
Abstracts
Results: The upper limit of the reference intervals of the different age groups is shown in Table 1. Though the sample collection was evenly distributed among the seasons, we did not observe a seasonal effect (F = 0.84, p = 0.47). Table 1 Upper limit of normal of Antistreptolysin O titer calculated by the Robust method (CLSI C28-A3). Age group
N (%males)
Outliers Tukey's method
ASO-ULN
90% Confidence interval
≤ 5 years
28 (57%)
3
216.74 IU/ml
14 3
539.10 IU/ml 340.50 IU/ml
164.71 to 268.77 Derived by Bootstrap resampling 495.97 to 581.06 289.26 to 409.15
6 to 15 years 192 (50%) ≥ 16 years 50 (42%)
Conclusions: The highest ASO titers were seen in children between the ages of 6 and 15 years. doi:10.1016/j.clinbiochem.2011.06.055
P545 Do diet restrictions reduce the number of positive results for the fecal occult blood test? R. Bunyan, K.L. Schnabl, T.N. Higgins, L. Denesiuk DynaLIFEDx, #200, 10150–102 St, Edmonton, Alberta, T5J 5E2, Canada Objective: Fecal occult blood test (FOBT) screening has been shown to decrease the incidence and mortality from colorectal cancer. To increase public awareness and to encourage patient compliance, a provincial campaign was launched and dietary restrictions for fecal occult blood testing in Alberta were removed on January 19, 2009. Methods: Subjects refrained from vitamin C supplementation and specimens were kept at room temperature for 72 h to remove peroxidases prior to performing the FOBT by the guaiac method. Data for the FOBT before and after the abolition of dietary restrictions was extracted from the laboratory information system. The positivity rate for the FOBT in urban and rural populations was compared. Results: Physicians reported an increase in the absolute number of positive results leading to an increased number of colonoscopies. For the year prior to abolition of dietary restrictions, the positivity rate in Edmonton and the rural communities was 1.80% and 1.79%, respectively; whereas for the year after it was 1.71% and 1.76%. The number of samples tested increased by almost 100% from January 2008 to December 2010. Conclusions: The removal of dietary restrictions dramatically improved patient compliance, had no significant impact on the positivity rate, and markedly reduced the number of telephone calls to the clinical chemists regarding clarification of dietary restrictions. The simultaneous change to the laboratory methods reduced interference from dietary peroxidases. doi:10.1016/j.clinbiochem.2011.06.056
P546 Validation of an enzyme immunoassay (EIA) for quantification of free testosterone (fTE) in serum J.L.V. Shaw a,b, L. Grossi c, I.M. Blasutig a,b, P.M. Yip a,b a Laboratory Medicine Program, University Health Network, Toronto, Ontario, Canada b Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada c Inter Medico, Markham, Ontario, Canada
Objective: To evaluate the Diagnostic Biochem Canada (London, ON) EIA method for the measurement of serum free testosterone (fTE). Methods: Imprecision was determined by measurement of BioRad Immunoassay Plus quality control material using two reagent lots over four plates. Linearity was assessed using six levels of calibrator material, measured in duplicate. The claimed EIA sensitivity was verified by measurement of the zero calibrator. Patient serum samples (n = 60) sent to Toronto General Hospital for fTE measurement were used for method comparison against the established RIA method (Siemens DPC). EIA analyses were performed in duplicate and compared to the RIA results using linear regression analysis. Reference interval studies were performed using samples from apparently healthy individuals (n = 23 male; n = 23 female). Antibodies used in both the EIA and RIA methods are specific for free testosterone and the assay procedures have been optimized to maintain the existing equilibrium between bound and free testosterone in patient serum. Results: The EIA method showed acceptable imprecision with CVs less than 10% for low (4 pmol/L; 9.5%), medium (25 pmol/L; 5.2%) and high (100 pmol/L; 7.3%) fTE levels of QC material. The EIA method was linear within the stated analytical measuring range of 0.9-433 pmol/L and agreed with the manufacturer's claimed limit of detection. Linear regression analysis identified the relationship between RIA(x) and EIA(y) measurements as: y = 1.037x − 5.97. The correlation coefficient for the two methods was 0.757. The stated reference range for fTE in females was verified, however further studies are needed for males due to several values which fell below the stated range. Conclusions: The fTE EIA demonstrated acceptable performance and produced results comparable to those made by RIA, although the local reference interval for males may be lower than stated. doi:10.1016/j.clinbiochem.2011.06.057
P547 Comparision of hemoglobin A1c (HbAIc) measurement in whole blood vs measurement in blood extracted from dried blood spots (DBS) using the tina-quant hemoglobin A1c GEN. 2 method on the cobas integra 400 plus analyzer J.L.V. Shaw a,b, D. Konforte a,b, B. Hoffman a,b, A. Azad a a Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada b Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada Objectives: To optimize HbA1c measurement from DBS on the Cobas Integra 400 analyzer and to compare HbA1c results obtained from DBS with those from whole blood. Methods: The optimal number of 3 mm punched discs and extraction time required to apply the Hemolysate Application of the Tina-quant Gen 2 method on the Cobas Intergra 400 to the measurement of HbA1c from DBS was determined. DBS were prepared from EDTA-anticoagulated blood samples (n = 48) sent for routine measurement of HbA1c. HbA1c measurements from DBS were compared (EP5-A2 CLSI) to HbA1c measured from the corresponding whole blood by the Cobas Integra Whole Blood Application protocol of the Tina-quant Gen 2 method. DBS with high (0.095), medium (0.063) and low (0.048) levels of HbA1c were used to determine imprecision (20 days). Linearity was assessed over a range of hematocrits and haemoglobin concentrations. Results: Three 3 mm DBS incubated in 500μL of hemolysis reagent for 3 hours was optimal. Comparison between DBS (y) and whole blood (x) HbA1c gave y = 0.94x + 0.36; R 2 0.99. The DBS method