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U Schenck

Publications and source records attributed to U Schenck.

45 records · Page 3Linked to original sources
PubMedDate not supplied

Detection of false negative Pap smears by rapid reviewing. A metaanalysis.

OBJECTIVE: To explore the diagnostic validity of rapid reviewing (RR) as a quality control method in cytologic laboratories. STUDY DESIGN: Fourteen studies dealing with the detection of false negative Pap smears by RR were included in a metaanalysis. RESULTS: The overall additional yield of positive slides, expressed as the percentage of all reviewed slides, is: 0.18% (95% confidence interval [CI]: .14-.21) for all cytologic abnormalities; 0.07% (CI: .05-.09) for squamous intraepithelial lesions (SIL) and 0.02% (CI: .01-.03) for high grade SIL. The false negative rate of primary screening, evaluated by RR, was 2.0% (CI: 1.5-2.6) for all cytologic abnormalities and 1.4% (CI: .8-2.1) for high grade SIL. The specificity of rapid rescreening was estimated as 97.2% (CI: 96.4-98.1). The positive predictive value of suspicion at RR is about 8.8%. Seven references contained historical data on full rescreening of a random sample of slides reported originally as negative. The results were also pooled and compared with RR. Complete rescreening is more sensitive, but if applied on only 10% of the negative workload, it would yield, on average, 4.7 times fewer extra positives, 5.6 times fewer SIL and 7.9 times fewer high grade SIL in comparison with RR of all sides. CONCLUSION: RR of all smears initially reported as nonpositive is a more effective and a fortiori a more cost effective quality control method in comparison with full rescreening of a 10% random sample.

Cell Biology↗
PubMedDate not supplied

Terminology. International Academy of Cytology Task Force summary. Diagnostic Cytology Towards the 21st Century: An International Expert Conference and Tutorial.

ISSUES: Differences in type, structure, quality of health care systems and availability of resources influence reporting systems. In most countries, individual systems have a long history of usage that might preclude adoption of a uniform terminology worldwide. CONSENSUS POSITION: It is desirable but unrealistic at this time to aim for a unified terminology worldwide. It should be the stated objective of the International Academy of Cytology to serve as an umbrella organization for various terminologies and enhance mutual understanding and cooperation. Translation tables of equivalent terms have been created to allow increased communication. Consensus has been achieved in defining essential elements required of any terminology system: (1) the report must be text based: numerical Papanicolaou class designations alone are inadequate; (2) an assessment of the adequacy of the sample should be included; and (3) the diagnosis must address the primary purpose of cervical cytology: to indicate the presence or absence of epithelial abnormalities. Incorporating additional elements within a terminology system may be more or less appropriate, depending on the setting in which the system is used. ONGOING ISSUES: Despite the cited problems in adopting a uniform terminology worldwide, a single system would have many advantages in terms of communication and research and may be a long-term goal worth pursuing. Countries are invited to present their individual national terminology systems and participate in an ongoing dialogue, critically evaluating the advantages and disadvantages of all systems.

Cervix Uteri↗
PubMedDate not supplied

Computerized screening devices and performance assessment: development of a policy towards automation. International Academy of Cytology Task Force summary. Diagnostic Cytology Towards the 21st Century: An International Expert Conference and Tutorial.

ISSUES: The extension of automation to the diagnostic assessment of clinical materials raises issues of professional responsibility, on the part of both the medical professional and designer of the device. The International Academy of Cytology (IAC) and other professional cytology societies should develop a policy towards automation in the diagnostic assessment of clinical cytologic materials. CONSENSUS POSITION: The following summarizes the discussion of the initial position statement at the International Expert Conference on Diagnostic Cytology Towards the 21st Century, Hawaii, June 1997. 1. The professional in charge of a clinical cytopathology laboratory continues to bear the ultimate medical responsibility for diagnostic decisions made at the facility, whether automated devices are involved or not. 2. The introduction of automated procedures into clinical cytology should under no circumstances lead to a lowering of standards of performance. A prime objective of any guidelines should be to ensure that an automated procedure, in principle, does not expose any patient to new risks, nor should it increase already-existing, inherent risks. 3. Automated devices should provide capabilities for the medical professional to conduct periodic tests of the appropriate performance of the device. 4. Supervisory personnel should continue visual quality control screening of a certain percentage of slides dismissed at primary screening as within normal limits (WNL), even when automated procedures are employed in the laboratory. 5. Specifications for the design of primary screening devices for the detection of cervical cancer issued by the IAC in 1984 were reaffirmed. 6. The setting of numeric performance criteria is the proper charge of regulatory agencies, which also have the power of enforcement. 7. Human expert verification of results represents the "gold standard" at this time. Performance characteristics of computerized cytology devices should be determined by adherence to defined and well-considered protocols. Manufacturers should not claim a new standard of care; this is the responsibility of the medical community and professional groups. 8. Cytology professionals should support the development of procedures that bring about an improvement in diagnostic decision making. Advances in technology should be adopted if they can help solve problems in clinical cytology. The introduction of automated procedures into diagnostic decision making should take place strictly under the supervision and with the active participation and critical evaluation by the professional cytology community. ONGOING ISSUES: Guidelines should be developed for the communication of technical information about the performance of automated screening devices by the IAC to governmental agencies and national societies. Also, guidelines are necessary for the official communication of IAC concerns to industry, medicolegal entities and the media. Procedures and guidelines for the evaluation of studies pertaining to the performance of automated devices, performance metrics and definitions for evaluation criteria should be established.

Automation↗
PubMedDate not supplied

Evaluation of costs and benefits of advances in cytologic technology. International Academy of Cytology Task Force summary. Diagnostic Cytology Towards the 21st Century: An International Expert Conference and Tutorial.

ISSUES: Uterine cervical cytology smears are among the most cost-effective cancer prevention interventions available, but they are not infallible, and new or modified technologies have been and will be proposed to improve diagnostic accuracy. Before these new technologies are accepted, their performance attributes will be carefully studied and defined. Equally important in this era of fiscal constraints are cost/benefit analyses, for which we review certain guidelines. CONSENSUS POSITION: In an effort to control rising costs in the health care sector, there has been a strong incentive to move toward a market system, and a variety of forces are acting to drive down expenditures. These same pressures will continue to be brought to bear on the providers of cervical cytology services. It must be emphasized that the technical knowledge required to define cost-effective medical practice lies within the medical profession itself, which must recognize the following: (a) Resources are finite; (b) Elimination of fraud, abuse and waste is not enough to bring health care expenditures down to levels considered acceptable to government and business; (c) The medical profession must take the responsibility to identify the health and economic consequences of the services it provides and make wise recommendations for allocation of resources to optimize health consequences. The analysis of costs and benefits must be viewed from a societal perspective and presented in terms of the marginal impact on current practice. This does not mean that new technologies must reduce cost; on the contrary, improvements in health can be expected to come at a price, but at a price commensurate with value gained in lives saved or in added quality adjusted life years. To be of value, a new technology for cervical cytology must be more effective in preventing cervical carcinoma. Dysplasia is considered a precursor of carcinoma, and detection of dysplasia has been a surrogate for prevention of cervical carcinoma, but dysplasia does not always lead to carcinoma, least of all mild dysplasia, and policy makers ultimately will insist that a favorable change in health outcome be effected by new technology before it is allocated resources. Alternatively, new technologies may lower cost, perhaps by modifying screening or rescreening procedures according to known risk; by improved cytopreparatory techniques that simplify, improve or speed screening; or by monitoring devices that minimize screening error. In each case the performance attributes of the instrument or human instrument process should be evaluated in the intended use environment. ONGOING ISSUES: While current cervical cytology methodology is one of the most effective means of cancer prevention, there continues to be development of new techniques to increase the sensitivity and specificity of this test. With present fiscal constraints, these will be subject to stringent cost/benefit analyses in which the medical profession must play a key role. Such analyses can be quite complicated, considering the additional costs or cost savings of clinical follow-up procedures and the reliability of dysplasias detected by cytology as a surrogate for cervical carcinoma in calculating quality of life years saved.

Attitude of Health Personnel↗
PubMedDate not supplied

Quality assurance by continuous recording of the microscope status.

OBJECTIVE: To assess continuous recording of the microscope status for quality assurance. STUDY DESIGN: Using a special microscope with coordinate registration and objective decoding, 8,653 cervical smears were read by five experienced cytotechnologists. Cytotechnologists could check their screening pattern on a TV monitor. Stage position and magnification were registered every 20 msec. RESULTS: The average screening time per case was 3.5 minutes followed by an approximately two-minute intercase interval. Daily workload profiles were generated to check compliance with workload regulations. Average screening time over a day and over a week was rather constant. CONCLUSION: Our experience demonstrates that continuous coordinate registration can be easily implemented as a method of quality assurance in routine cytology.

Female↗
PubMedDate not supplied

Cytology of the human seminiferous epithelium.

The appearances in cytologic specimens of the principal cell types in the normal human seminiferous epithelium are described and illustrated. Sertoli cells, which are larger than spermatogenic cells, are characterized by a slightly basophilic, ill-defined cytoplasm of triangular, elongated or columnar shape; the cytoplasm may be vacuolated and may contain spermatozoa. The nuclei of Sertoli cells are round, with a uniformly finely granulated chromatin and a single nucleolus. Spermatogenic cells are round or oval and show scanty cytoplasm with deeper basophilia and well-defined cytoplasmic borders. Multinucleation is common in spermatogenic cells. The Sertoli cells constitute a very homogeneous cell population as compared to the spermatogenic cells, which show several distinct cell types (spermatogonia, primary and secondary spermatocytes, spermatids and spermatozoa) whose nuclear structures depend on the stage of meiosis. Both cell types may occur as naked nuclei. Some problems of cell classification are discussed.

Biopsy, Needle↗
PubMedDate not supplied

[Comparison between testicular biopsies and biopsy smears in azoospermia].

The diagnostic results of testicular biopsies were compared to the results of biopsy smear cytology in 25 patients with azoospermia. Sufficient correct diagnosis was made cytologically in 23 cases. In two cases of incomplete spermatogenetic arrest, cytology was inconclusive and no cytological diagnosis could be made. The diagnostic results are based on a rough population analysis. Evaluation of the tubuli, basal membrane and interstitial tissue can not be made in cytological material. Good diagnostic results can only be obtained if a satisfactory cytological specimen is examined i.e. material containing spermatogenetic and/or Sertoli cells.

Biopsy↗
PubMedDate not supplied

Fine needle aspiration and mammary secretion, cytology and core biopsy.

Cytology of breast secretions, fine needle aspiration cytology (FNA) of the breast and core biopsy of the breast have been used for a long time. However, the application of the different approaches and their benefit for patients is still discussed. While FNA has challenged surgical biopsy since many years, additionally, core biopsy gets more important due to simplification of handling and decreasing tissue trauma. In conjunction with imaging techniques the number of necessary surgical biopsies has dramatically decreased in many places. Characteristics of the two approaches are tabulated in this contribution, which focuses on symptomatic patients presenting with either lumps of the breast or mammary secretions. Cytologic examination of breast secretions allows early diagnosis of intraductal carcinoma in situ and invasive ductal carcinoma in about 1% of all breast secretions. Careful localisation of the lesions is necessary. Most cases of breast cancer do not cause secretions, so, breast secretion cytology will contribute only in a minority of cases. In cases showing both, breast secretion and lumps, these should be considered as possibly caused by different lesions.

Biopsy↗