Biomedical subjects

Lynn C Allen

Publications and source records attributed to Lynn C Allen.

4 recordsLinked to original sources

PubMed2005

A randomised controlled trial of biopsy forceps and cannula aspiration for transcervical chorionic villus sampling.

OBJECTIVE: This trial compared two instruments for transcervical chorionic villus sampling (CVS). DESIGN: Randomised controlled trial. SETTING: Regional university prenatal diagnosis and treatment centre. POPULATION: Two hundred women were randomised at 10(+0)-12(+6) weeks of gestation to transcervical CVS using cannula aspiration (CA) or biopsy forceps (BF). METHODS: Women undergoing indicated CVS signed informed consent. Randomisation after decision to perform transcervical CVS. MAIN OUTCOME MEASURES PRIMARY OUTCOME: the rise in maternal serum alpha-fetoprotein (alpha-FP). SECONDARY OUTCOMES: (i) placental trauma (fetomaternal haemorrhage [FMH]); (ii) laboratory, procedure, and cytogenetic results and pregnancy outcomes; (iii) patient and operator satisfaction; and (iv) economic analyses. Analyses were performed by intention to treat. RESULTS: The -FP rise did not differ between groups; there was no other evidence of placental trauma. BF were better tolerated by women, provided culturable tissue, after fewer instrument passes, with greater ease and in less time. BF were associated with cost savings. CONCLUSIONS: Unlike -FP, other markers of FMH were unaltered, questioning the reliability of alpha-FP as an indicator of FMH. Compared with CA, transcervical BF caused comparable placental trauma, appeared to be similarly effective and safe and were preferred by operators and patients.

Biopsy, Needle↗

PubMed2003

Analytical evaluation of hemoglobin A(1c) dual kit assay on Bio-Rad Variant II: an automated HPLC hemoglobin analyzer for the management of diabetic patients.

OBJECTIVES: To evaluate the analytical performance of the Bio-Rad Variant II HbA(1c) dual kit assay. DESIGN AND METHODS: Precision, carryover, linearity and analytical range were investigated. 139 patients' HbA(1c) results analyzed by the Variant II were compared to the Variant I method. 49 blood samples analyzed by the Variant II at Toronto Medical Laboratories (TML) were compared to the Variant II at Hospital for Sick Children (HSC). RESULTS: Total imprecision was less than 2% for the Variant II assay. The method had a wide analytical range with no carryover. HbA(1c) results were not changed after switching back and forth from the beta thalassemia to HbA(1c) assay. The Variant II showed an average of 0.0027 negative bias compared to the Variant I method. There was an average of 0.0020 negative bias for HbA(1c) results on the Variant II at TML compared to the Variant II at HSC. CONCLUSIONS: HbA(1c) analysis on the Variant II HbA(1c) dual kit is a relatively fast and reproducible method.

Chromatography, High Pressure Liquid↗

PubMed2003

Outcome validation of the Beckman Coulter access analyzer in a second-trimester Down syndrome serum screening application.

BACKGROUND: Mid-trimester maternal serum alpha-fetoprotein (AFP) and unconjugated estriol (uE3) are 30% lower and human chorionic gonadotropin (hCG) is twofold higher in Down syndrome pregnancies compared with unaffected pregnancies. In maternal serum screening, patient-specific risks are calculated using published gaussian frequency distribution parameters for these three markers obtained with previously available immunoassays. New immunoassays must generate similar distribution parameters if the accuracy of assigned risks and overall performance of prenatal screening are to be maintained. METHODS: Agreement between the Beckman Coulter Access and the Bayer Immuno 1 assays for AFP and hCG and the Amersham Amerlex-M RIA for uE3 was assessed in 558 fresh sera. Precision was measured over 6 weeks. Median concentrations were calculated by regression of 568 Caucasian singleton pregnancy samples against gestational age in days. Frozen mid-trimester sera from 44 confirmed Down syndrome singleton pregnancies (cases) were selected without conscious bias for reanalysis, and each case was matched with five control specimens from unaffected pregnancies. Serum markers were expressed as the multiple of the median (MoM) concentration derived from the control samples, corrected for maternal weight and converted to their log-equivalent values. Normality was assessed using probability plots and the Shapiro-Wilk W-test. Gaussian distribution parameters were compared with established values, and Down syndrome risk calculations were assessed with a commonly used risk algorithm. RESULTS: The Access AFP and hCG assays had consistent proportional agreement with the established assays, whereas agreement between the uE3 methods was less consistent. Analytical imprecision was 3-6% at mid-trimester concentrations. Normal distributions were obtained for the log MoM values of all three markers in both the Down syndrome and unaffected populations, and their gaussian distribution parameters compared well with established values. The performance of the Access assays in an established trivariate risk algorithm for Down syndrome was equal to the performance exhibited by traditional methods. CONCLUSION: The Beckman Coulter Access analyzer provides valid mid-trimester serum AFP, uE3, and hCG results and risk assessments when applied in a prenatal Down syndrome screening service.

Biomarkers↗

PubMed2003

IFCC handbook on Master Program in clinical laboratory sciences.

This document summarizes the steps in development of a new IFCC Master Program and outlines some of the ways the IFCC would assist in setting up such a regional Program. This is intended to be of assistance to those who wish to embark on such an endeavour.

Education, Graduate↗