Biomedical subjects

Edward Wang

Publications and source records attributed to Edward Wang.

At least 19 recordsLinked to original sources

PubMed2006

Acculturation, social alienation, and depressed mood in midlife women from the former Soviet Union.

Level of acculturation has been linked to depressed mood in studies across culturally diverse immigrant groups. The purpose of this study was to determine the effects of acculturation, social alienation, personal and family stress, and demographic characteristics on depressed mood in midlife immigrant women from the former Soviet Union. Structural equation modeling showed that higher acculturation scores, measured by English language and American behavior, were indirectly related to lower scores for depressed mood. Higher acculturation levels promoted mental health indirectly by reducing social alienation and, subsequently, lowering family and personal stress, both of which had direct relationships to symptoms of depression. These findings support the ecological framework that guided our research and point to the importance of focusing on contextual factors in developing interventions for new immigrants.

Acculturation↗

PubMed2006

Recruitment of African American women to a walking program: eligibility, ineligibility, and attrition during screening.

The purposes of this study were to identify strategies successful in the recruitment of African American (AA) women to a home-based walking program and to examine factors that contribute to attrition, eligibility, and ineligibility during the recruitment screening protocol. Of the 696 women who contacted the researchers, 281 (40.4%) women enrolled in the study, 227 (32.6%) were lost to attrition, and 188 (27%) were ineligible. Those not enrolled due to attrition during screening or ineligibility reported more family risk for cardiovascular disease (CVD) and lived in neighborhoods with higher poverty. Although our recruitment strategies may have been successful in attracting low-income AA women, we were not as successful in preventing their attrition during the screening protocol, particularly for those living in poorer neighborhoods.

Adult↗

PubMed2006

Menopausal transition symptoms in midlife women living with fibromyalgia and chronic fatigue.

We aimed to determine how menopausal transition symptoms cluster across 216 midlife women with fibromyalgia, chronic fatigue syndromes (FMS/CFS), or both and subsequently to compare symptom factor severity scores by menopausal status among these women and compare symptom reporting with prior community-based samples of women without obvious illness. We designed a cross-sectional telephone survey of 216 women aged 35 to 55, diagnosed with FMS/CFS, symptomatic in the prior 6 months, and without hysterectomy. Thirty-six of 61 symptoms loaded on five factors: aroused/anxious mood, depressed mood/withdrawal, musculoskeletal, gastrointestinal (GI), and vasomotor. Peri- and postmenopausal women had higher symptom severity scores for musculoskeletal, GI, and vasomotor factors but not mood factors. Symptoms for the women we studied who had FMS/CFS clustered similar to those in previous community-based samples of midlife women without major illness; however, the number of women experiencing symptoms was much higher among our sample.

Adaptation, Psychological↗

PubMed2006

Women's health issues with fibromyalgia syndrome.

BACKGROUND: Fibromyalgia syndrome (FMS) involves multiple sensory, somatic, and cognitive symptoms that are bound to affect or be affected by physical and mental health status and behavioral components of daily life. METHODS: From a telephone survey of 442 women with and 205 women without FMS as volunteers, data were compared on (1) general health status, (2) reproductive and sleep-related diagnoses, and (3) lifestyle health behaviors. RESULTS: All multiple or logistics regression analyses for group differences were controlled for age, body mass index (BMI), race, employment status, marital status, having a college degree, low household income, and having ever been diagnosed with depression, with a Bonferroni p value correction for multiple indicators. Accordingly, FMS negatively impacted both perceived physical and mental health status, although relatively more so for physical (p < 0.017). Women with FMS were more likely to have had reproductive health or sleep-related diagnoses, including premenstrual syndrome, dysmenorrhea, breast cysts, bladder cystitis, sleep apnea, restless leg syndrome, and abnormal leg movements (p < 0.0125). They were calculated to use less than half as many calories per week as control women (689 +/- 1293 vs. 1499 +/- 1584 kcal/week, p < 0.05) and had more sleep pattern difficulties (p < 0.0125), more negative changes in sexual function (greater odds for 5 of 10 indicators at p < 0.005), and lower alcohol use (odds ratio = 0.39, p < 0.05). CONCLUSIONS: Patients with FMS deserve careful assessment for reproductive conditions and sleep-related functional disorders. Besides more research into mechanisms underlying symptoms, intervention testing specifically to alleviate sleep problems, low physical activity levels, and sexual dysfunction should be paramount.

Activities of Daily Living↗

PubMed2006

The potential for failure in gynecologic regulatory proficiency testing with current slide validation criteria: results from the College of American Pathologists Interlaboratory Comparison in Gynecologic Cytology Program.

CONTEXT: Current regulatory proficiency testing scoring results in an automatic failure for identifying high-grade squamous intraepithelial lesion (HSIL) as negative. OBJECTIVE: The College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology data from January 2004 to April 2005 were analyzed to estimate the percentage of failure based on negative responses for HSIL and validation criteria. DESIGN: More than 15,000 participants received field-validated and educational slide sets for conventional, ThinPrep, and SurePath modules. Educational sets fulfilled the validation criteria of the Center for Medicare and Medicaid Services, which required the consensus diagnosis of biopsy-proven HSIL (not field-validated) after review by 3 pathologists. The College of American Pathologists field validation required at least 20 responses to the HSIL+ series, with 70% matched to HSIL+ (standard error < or = 0.05). Minimum regulatory proficiency testing failure estimates were based on incorrect negative responses for the reference category of HSIL. RESULTS: For both cytotechnologists and pathologists, there was a statistically significant higher failure rate for slides that were not field-validated versus those that were field-validated. In conventional modules, 5.3% of the slides that were not field-validated were called negative, versus 1.2% of the field-validated slides. In all liquid-based preparations, 4.0% of the non-field-validated versus 2.2% field-validated slides were called negative. Pathologists would have failed more often than cytotechnologists for the slides that were not field-validated, whereas there was no statistical difference in failure performance with field-validated slides. CONCLUSIONS: Failures were significantly greater with the slides that were not field-validated for both conventional and liquid-based preparations (ThinPrep only) and have implications for both regulatory proficiency testing and expert legal review. Poor performance of pathologists relative to that of cytotechnologists may reflect a lack of prescreening of slides or scope of practice issues.

Clinical Competence↗

PubMed2006

Interobserver agreement on microfollicles in thyroid fine-needle aspirates.

CONTEXT: Although microfollicles are a well-known feature of follicular neoplasms in fine-needle aspirates of the thyroid, the level of agreement about classifying groups as microfollicles is not known. OBJECTIVE: To determine what features are present in groups that are consistently classified as microfollicles. DESIGN: We showed 45 small groups of follicular cells each composed of fewer than 50 cells from fine-needle aspirates of the thyroid to 12 members of the College of American Pathologists Cytopathology Committee, who then classified the groups into microfollicles, macrofollicles, and indeterminate groups. RESULTS: Twenty groups were consistently classified as microfollicles, 7 groups as macrofollicles, and 18 groups as indeterminate. Cases that were consistently classified as microfollicles were composed of fewer than 15 cells (19/20 cases), were arranged in a circle with a lumen (13/20 cases) that was at least two-thirds complete (12/20 cases), and were flat (18/20 cases). Cases that were classified as macrofollicular had between 8 and 35 cells, were arranged in sheets composed of at least 15 cells (5/7 cases) or rows of 8 cells (2/7 cases), and were flat (7/7 cases). In contrast, cases that were indeterminate were composed of either 3-dimensional groups (5/18 cases), flat groups of fewer than 10 cells (11/18 cases), or single cells (1/18 cases). CONCLUSION: Not all small groups of follicular cells are consistently classified as microfollicles, and some are more often classified as macrofollicles. The criteria described here for reproducible microfollicles (<15 cells, arranged in a circle that is at least two-thirds complete, and flat) may help improve the agreement in classification of microfollicles and lead to more consistent classification of thyroid fine-needle aspirates.

Adenocarcinoma, Follicular↗

PubMed2006

Leukemia/lymphoma in cerebrospinal fluid: distinguishing between cases that performed well and poorly in the College of American Pathologists Interlaboratory Comparison Program in Non-gynecologic Cytology.

CONTEXT: Although the cytologic features of leukemia/lymphoma in cerebrospinal fluid specimens are well known, the correlation of these features with the ability of cytologists to identify this tumor have not been well studied. OBJECTIVE: To identify the morphologic features of leukemia/lymphoma in cerebrospinal fluid that are associated with good performance and poor performance in an educational interlaboratory comparison program; and to identify the morphologic features associated with how well a slide performs with regard to its reference diagnosis. DESIGN: The performance of 147 cases of leukemia/lymphoma in the College of American Pathologists Interlaboratory Comparison Program in Non-gynecologic Cytology was analyzed. The cytologic features of a subset of 31 cases composed of relatively equal numbers of Romanowsky-stained and Papanicolaou-stained specimens were further evaluated, and those that performed poorly (n = 12) were compared with those that performed extremely well (n = 19). RESULTS: For all cases of leukemia/lymphoma in the program, the rate of misclassification as benign for cases with Papanicolaou stain was significantly higher than for those with Romanowsky stain (9.5% vs 2.6%, P < .001). Compared with cases that performed well, slides that performed poorly were more likely to have less than 200 abnormal cells (42% vs 5%, P = .02). The size of the tumor cells and preservation were not significant. CONCLUSION: Cases of specimens of leukemia/lymphoma in cerebrospinal fluid are more likely to be misdiagnosed as benign if they are Papanicolaou-stained or have 200 abnormal cells.

Cytodiagnosis↗

PubMed2006

Cytologic features of adenocarcinoma, not otherwise specified, in conventional smears: comparison of cases that performed poorly with those that performed well in the College of American Pathologists Interlaboratory Comparison Program in cervicovaginal cytology.

CONTEXT: Characteristic cytologic features have been identified that distinguish cases that are consistently identified from those that are sometimes missed in the College of American Pathologists Gynecologic Cytology Program for a variety of different lesions and preparations. OBJECTIVES: To compare the cytologic features of cases of adenocarcinoma, not otherwise specified (NOS), in conventional smears that perform poorly and well. DESIGN: The cytologic features of 21 conventional smear cases of adenocarcinoma, NOS, that performed poorly in the College of American Pathologists Interlaboratory Comparison Program were compared with 17 cases that performed extremely well. RESULTS: Cases that performed well were significantly more likely to have greater than 1000 abnormal cells (P = .006), greater than 100 large abnormal cells (P = .006), large nuclei (P < .001), marked nuclear atypia (P = .02), and hyperchromasia (P = .02). Repair-like features were rare in both groups and were not significant (P = .71). CONCLUSION: Conventional smears with a diagnosis of adenocarcinoma that were consistently identified were significantly more likely to have more abnormal cells, larger abnormal cells, larger nuclei, marked atypia, and hyperchromasia than cases that performed poorly.

Adenocarcinoma↗

PubMed2006

Hyperchromatic crowded groups in cervical cytology--differing appearances and interpretations in conventional and ThinPrep preparations: a study from the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology.

CONTEXT: The practice of gynecologic cytology requires that high-grade squamous intraepithelial lesion (HSIL) be precisely recognized. In this regard, hyperchromatic crowded groups are known to be difficult to classify in conventional gynecologic cytology, but whether this is true in ThinPrep specimens is uncertain. OBJECTIVE: To assess whether hyperchromatic crowded groups of cells in challenging HSIL cases are a problem in ThinPrep preparations, and whether these groups differ in appearance from those of conventional smears. DESIGN: Sixteen images were taken from both conventional smears and ThinPrep slides that had a reference diagnosis of HSIL in the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology, but had performed poorly on subsequent participants' reviews. These 32 representative images were of hyperchromatic crowded groups and were classified by 20 Cytopathology Resource Committee members (17 pathologists and 3 cytotechnologists), who were masked to the reference diagnosis. A consensus classification was derived using the majority opinion of the individual reviewers. Finally, 5 cytologic features were assessed for those images that were interpreted as abnormal by the consensus classification. RESULTS: None of the 32 images was uniformly interpreted as either benign, squamous lesion, or glandular lesion on individual review. Only 27% of individual interpretations of conventional smear images and 15% of ThinPrep images were interpreted as HSIL/squamous cell carcinoma (P < .001). Individual interpretations of ThinPrep images as glandular lesions (60%) were more often made than those of conventional smears (44%, P < .001). The consensus interpretation of ThinPrep images was glandular lesion in 75% of cases, whereas fewer than 50% of the consensus interpretations of conventional smear images were in this category. Conventional smear images were characterized by elongate nuclei (43%) and large nuclei (71%), whereas ThinPrep images more often showed rounded smooth edges (53%) and small nuclei (80%), and were recognized as a glandular lesion. CONCLUSIONS: Hyperchromatic crowded groups of cells are a source of difficulty in challenging HSIL cases for both conventional smears and ThinPrep specimens. In conventional smears, these groups are more likely to be labeled as a squamous lesion, owing to their elongate and large nuclei. In ThinPrep specimens, however, these groups are more likely to be labeled as glandular lesions, owing to their smooth contoured borders and small nuclei.

Carcinoma, Squamous Cell↗

PubMed2006

Fine-needle aspiration of papillary thyroid carcinoma: distinguishing between cases that performed well and those that performed poorly in the College of American Pathologists Nongynecologic Cytology Program.

CONTEXT: Although the cytologic features of papillary thyroid carcinoma in fine-needle aspiration specimens are well known, the correlation of these features with the ability of cytologists to identify this tumor has not been well studied. OBJECTIVE: To compare the cytologic features of cases of papillary thyroid carcinoma that performed poorly with those of cases that performed well. DESIGN: The cytologic features of 13 cases of papillary thyroid carcinoma from the College of American Pathologists Nongynecologic Cytology Program that performed poorly were compared with those of 15 cases that performed well. RESULTS: Compared with cases that performed well, cases that performed poorly were significantly more likely to lack marked nuclear enlargement (38% vs 100%, P < .001), lack pale chromatin (8% vs 47%, P = .04), and lack intranuclear inclusions (8% vs 53%, P = .02). The differences between the 2 groups in staining, type of preparation, nuclear grooves, nuclear crowding, colloid, cellularity, nuclear pleomorphism, and Hurthle cell change were not significant. CONCLUSIONS: Cases of papillary thyroid carcinoma that lack marked nuclear enlargement, pale chromatin, and intranuclear inclusions are significantly more difficult to recognize than cases that have these features. Increased awareness of these types of cases might improve the performance of thyroid fine-needle aspiration in clinical practice.

Adenocarcinoma, Papillary↗

PubMed2005

Obesity prevalence among a group of Chicago residents with disabilities.

OBJECTIVE: To examine the prevalence of overweight, obesity, and extreme obesity in a predominantly minority group of adults with disabilities. DESIGN: Cross-sectional study using secondary data analysis. SETTING: Major university medical center. PARTICIPANTS: Adults with physical and cognitive disabilities (N = 306). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Direct measures of height and weight to classify subjects into 3 obesity categories: overweight (body mass index [BMI] range, 25-29.9 kg/m2), obese (BMI range, 30-39.9 kg/m2), and extreme obesity (BMI, > or = 40 kg/m2). RESULTS: People with disabilities, regardless of sex, race and ethnicity, or age, had significantly higher rates of overweight, obesity, and extreme obesity compared with people without disabilities. Extreme obesity (BMI, > or = 40 kg/m2) was approximately 4 times higher among people with disabilities than in the general population (odds ratio = 4.08; 95% confidence interval, 3.50-4.66). There were also substantial differences in obesity prevalence among people with disabilities, using actual measurement data, compared with self-reported data from previously published data sets. CONCLUSIONS: The disparity in excess body weight between people with and without disabilities, particularly in the category of extreme obesity, along with substantial differences in obesity prevalence between actual and self-reported data, show a critical need to better understand why these differences exist.

Adult↗

PubMed2005

Aerobic exercise training in stroke survivors.

Functional aerobic capacity among persons with stroke is severely compromised and may limit their full participation in community living. Even though aerobic conditioning can be potentially valuable to persons with stroke in reducing the risk of recurrent morbid events and improving overall quality of life, there is limited information on the specific dose of aerobic exercise (i.e., frequency, intensity, duration, and modality) that may achieve the most desirable health outcomes under the safest conditions in this population. Because of the many comorbidities associated with stroke (i.e., hypertension, heart disease, obesity, depression), specific recommendations for prescribing aerobic exercise must become more precise and be subsequently added to the treatment regimen for this large and diverse population. Future research must address optimal aerobic training programs necessary for reductions in cardiovascular risk factors and gains in functional status in stroke patients.

Activities of Daily Living↗

PubMed2005

Accessibility of health clubs for people with mobility disabilities and visual impairments.

OBJECTIVE: We sought to examine the accessibility of health clubs to persons with mobility disabilities and visual impairments. METHODS: We assessed 35 health clubs and fitness facilities as part of a national field trial of a new instrument, Accessibility Instruments Measuring Fitness and Recreation Environments (AIMFREE), designed to assess accessibility of fitness facilities in the following domains: (1) built environment, (2) equipment, (3) swimming pools, (4) information, (5) facility policies, and (6) professional behavior. RESULTS: All facilities had a low to moderate level of accessibility. Some of the deficiencies concerned specific Americans with Disabilities Act guidelines pertaining to the built environment, whereas other deficiency areas were related to aspects of the facilities' equipment, information, policies, and professional staff. CONCLUSIONS: Persons with mobility disabilities and visual impairments have difficulty accessing various areas of fitness facilities and health clubs. AIMFREE is an important tool for increasing awareness of these accessibility barriers for people with disabilities.

Persons with Disabilities↗

PubMed2005

Measuring the significance of field validation in the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology: how good are the experts?

CONTEXT: Expert opinion is often used as a gold standard for gynecologic cytology in the evaluation of new technologies, in the legal setting, and in the validation of cases for use in educational programs and proficiency testing. However, the reliability of expert opinion alone in selecting slides of a specific cytodiagnosis that can be reproducibly and reliably identified by subsequent reviewers has not been determined. OBJECTIVE: To assess the ability of expert opinion to select slides that are validated in subsequent reviews. DESIGN: In the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology, each case in every cytodiagnostic category is accepted for circulation only after review by 3 expert cytopathologists. The percentage of these cases that could not be reliably and reproducibly identified by program participants for each cytodiagnostic category ("failed field validation") was determined during the duration of the program from 1989 to 2004. RESULTS: More than 10,000 conventional smears and ThinPrep cases were selected by the expert panel for circulation. Of these selected slides, 19% of conventional smears and 15% of ThinPrep specimens failed field validation. Compared with the overall slide performance, significantly higher percentages (P < .001) of conventional smears with reference diagnoses of unsatisfactory (51.7%), repair (58%), or low-grade intraepithelial lesion (31.8%) and of ThinPrep specimens with reference diagnoses of unsatisfactory (54.5%) and repair (76.9%) failed field validation. In contrast, significantly lower percentages of conventional smears with reference diagnoses of squamous cell carcinoma (4.5%), high-grade squamous intraepithelial lesion (9%), Trichomonas vaginalis infection (11.7%), or herpes (9.9%) and of ThinPrep specimens with reference diagnoses of adenocarcinoma (5.1%), herpes (2.1%), and fungal organism consistent with Candida (8.4%) failed field validation (P < .001 for all). CONCLUSIONS: Between 15% and 19% of gynecologic cytologic cases that have been selected by expert cytopathologists as good examples of cytodiagnostic abnormalities fail field validation. The proportion of cases failing field validation varies with cytodiagnostic category, but it occurs in all cytodiagnostic entities.

Clinical Competence↗

PubMed2005

Measuring the significance of participant evaluation of acceptability of cases in the College of American Pathologists Interlaboratory Comparison Program in cervicovaginal cytology.

CONTEXT: The quality of gynecologic cytology slides within educational and proficiency testing programs may deteriorate during use. Participant evaluation of the acceptability of these slides subsequent to possible deterioration is not known. OBJECTIVE: To assess participants' evaluation of the acceptability of slides circulating within an educational gynecologic cytology glass slide program. DESIGN: The College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology is a peer comparison and educational program that evaluates the ability of the participants to correctly classify gynecologic cytology preparations. The program uses both expert review and field validation to select slides for the graded portion of the program. Participants were asked to assess the acceptability of slides within the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology, and their responses were assessed with respect to type of slide preparation, validation status, and reference diagnosis. In addition, we compared the cytodiagnostic discordancy rates of slides that were deemed acceptable by participants with those that were deemed unacceptable. SETTING: Participant assessments were derived from pathologists and cytotechnologists from cytology laboratories of all types. RESULTS: A total of 17,210 slide interpretations were reviewed, and 2.91% of the cases were labeled unacceptable by participants. For all slides, the percentage of cases called unacceptable varied from 1.65% for cases with a reference interpretation of herpes to 45% for cases with a reference interpretation of unsatisfactory. The percentage of slides deemed unacceptable was higher for validated slides than for educational slides (3.27% vs 2.55%, P = .006). The discordancy rate (to reference diagnosis series) for cases deemed unacceptable was significantly higher than the discordancy rate for cases deemed acceptable for both validated (10.39% vs 1.76%) and educational slides (21.72% vs 3.53%, P < .001). CONCLUSION: Greater than 97% of all slides in the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology were judged acceptable by participants. Despite expert review and field validation, a small percentage of slides (almost 3%) in this program were deemed unacceptable by participants. These results support the use of participant evaluation of cases to continually improve the quality of cases in this program.

Clinical Competence↗

PubMed2005

Cytologic features of squamous cell carcinoma in conventional smears: comparison of cases that performed poorly with those that performed well in the College of American Pathologists Interlaboratory Comparison Program in cervicovaginal cytology.

CONTEXT: Characteristic cytologic features have been identified that distinguish cases that are always identified from those that are sometimes missed in the College of American Pathologists Gynecologic Cytology Program for a variety of different lesions and preparations. OBJECTIVE: To compare the cytologic features of cases of squamous cell carcinoma in conventional smears that perform poorly and well. DESIGN: The cytologic features of 8 conventional smear cases of squamous cell carcinoma that performed poorly in the College of American Pathologists Interlaboratory Comparison Program were compared with 17 cases that performed extremely well. RESULTS: A total of 2387 individual interpretations were recorded. Of the 86 incorrect responses, 6.2% were for repair, and 0.8% were for Trichomonas. Cases that performed well were significantly more likely to have greater than 1000 dysplastic cells (16/17 vs 4/8, P = .02) and be keratinized (13/17 vs 1/8, P = .007). Obscuring inflammation and cell size were not significant. CONCLUSION: Conventional smears with a diagnosis of squamous cell carcinoma that were always identified were significantly more likely to have greater than 1000 cells and be keratinized than cases that performed poorly.

Carcinoma, Squamous Cell↗

PubMed2005

Creatinine measurement: state of the art in accuracy and interlaboratory harmonization.

CONTEXT: The National Kidney Disease Education Program recommends calculating glomerular filtration rate from serum creatinine concentration. Accurate creatinine measurements are necessary for this calculation. OBJECTIVE: To evaluate the state of the art in measuring serum creatinine, as well as the ability of a proficiency testing program to measure bias for individual laboratories and method peer groups. DESIGN: A fresh-frozen, off-the-clot pooled serum specimen plus 4 conventional specimens were sent to participants in the College of American Pathologists Chemistry Survey for assay of creatinine. Creatinine concentrations were assigned by isotope dilution mass spectrometry reference measurement procedures. PARTICIPANTS: Clinical laboratories with an acceptable result for all 5 survey specimens (n = 5624). RESULTS: The fresh frozen serum (FFS) specimen had a creatinine concentration of 0.902 mg/dL (79.7 micromol/L). Mean bias for 50 instrument-method peer groups varied from -0.06 to 0.31 mg/dL (-5.3 to 27.4 micromol/L), with 30 (60%) of 50 peer groups having significant bias (P < .001). The bias variability was related to instrument manufacturer (P < or = .001) rather than method type (P = .02) with 24 (63%) of 38 alkaline picric acid methods and with 6 (50%) of 12 enzymatic methods having significant biases. Two conventional specimens had creatinine concentrations of 0.795 and 2.205 mg/dL (70.3 and 194.9 micromol/L) and had apparent survey biases significantly different (P < .001) from that of the FFS specimen for 34 (68%) and 35 (70%) of 50 peer groups, respectively. CONCLUSIONS: Thirty of 50 peer groups had significant bias for creatinine. Bias was primarily associated with instrument manufacturer, not with type of method used. Proficiency testing using a commutable specimen measured participant bias versus a reference measurement procedure and provided trueness surveillance of instrument-method peer groups.

Bacteriological Techniques↗

PubMed2005

Comparison of pooled fresh frozen serum to proficiency testing material in College of American Pathologists surveys: cortisol and immunoglobulin E.

CONTEXT: The College of American Pathologists (CAP) provides proficiency testing (PT) surveys to laboratories around the world. OBJECTIVES: To compare diagnostic assay methods for serum/plasma cortisol and immunoglobulin (Ig) E in terms of their bias and precision, to determine how well CAP PT specimens simulate human serum, and to reassess proficiency test grading criteria in light of these findings. DESIGN: A participant-blinded, prospective trial. One vial of pooled fresh frozen serum (FFS) and 4 different admixtures of PT material (PTM) were sent to laboratories participating in PT surveys. PARTICIPANTS: Laboratories providing cortisol (>1000) or IgE (>230) results among the subscribers to the CAP surveys, Ligand (General) 2003, set K/KN-A and Chemistry 2003, set C-C. MAIN OUTCOME MEASURES: The main outcome measures were (1) bias among laboratories using the same method (peer groups), defined relative to the median of method means (MedMM); (2) imprecision as measured by the SD and coefficient of variation (CV) about each method mean; and (3) total error across laboratories for the FFS cortisol results, defined as |Bias Relative to Reference Method| + 2 SD. RESULTS: Cortisol method biases, relative to MedMM, ranged from -22% to 9% for the FFS challenge and from -24% to 36% for comparable PTM challenges. The method biases, relative to the reference method, ranged from -3% to 19% for the FFS challenge. The cortisol method CVs ranged from 4.2% to 13.6% for the FFS challenge and from 4.7% to 12.7% for comparable PTM challenges. Total error across laboratories ranged from 1.4 to 6.9 microg/dL (39 to 190 nmol/L) for the FFS challenge. Immunoglobulin E method biases, relative to MedMM, ranged from -8% to 9% for the FFS challenge and from -7% to 5% for comparable PTM challenges. The IgE method CVs ranged from 3.6% to 6.7% for the FFS challenge and from 3.4% to 9.8% for comparable PTM challenges. CONCLUSIONS: The bias for cortisol results was less with FFS than with PTM, but imprecision was comparable. The FFS MedMM was 8.5% higher than the reference value. Fresh frozen serum and PTM bias and imprecision for IgE methods were each less than 10%. Because some of the methods demonstrated greater bias when analyzing PTM than FFS, peer group grading of both these analytes is appropriate.

Clinical Laboratory Techniques↗