The exclusion of diagnostic methods from patentability by the EPC: a case for review?
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Diagnostic Techniques and Procedures↗
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Surveillance of childhood influenza virus infection: what is the best diagnostic method to use for archival samples?
Despite the clinical importance of influenza virus in pediatric respiratory infections, the optimal set of diagnostic tests to use when conducting studies using archival samples is not clear. In this study, we compared diagnostic tests for influenza virus in 75 children younger than 5 years of age who presented with symptomatic respiratory infection during one of four influenza seasons, had negative viral cultures for other respiratory pathogens, and had both an archival nasal aspirate obtained at the time of illness and serology spanning that influenza season. For all eligible children, we compared the results of viral culture performed at the time of collection with serology and PCR of archival nasal aspirates. Using real-time viral culture as the "gold standard," the test characteristics of PCR of archival nasal aspirates (sensitivity, 82%; specificity, 100%) and serology (sensitivity, 82%; specificity, 87%) were similar. The relatively low sensitivity of PCR of archival nasal samples in this study compared to that of PCR of fresh samples in a previous study suggests that RNA degradation occurred despite storage of the specimens at -70 degrees C. RNA degradation would also explain why only 11 (52%) of 21 archival nasal samples that had positive influenza virus cultures at the time of collection had positive repeat cultures in the summer of 2000. Thus, in archival specimens stored at -70 degrees C, PCR was more sensitive than viral culture. However, testing of fresh specimens had the highest yield in this study. Studies of optimal methods for specimen storage are needed.
Child, Preschool↗
Value of cytology as an adjunctive intraoperative diagnostic method. An audit of 2,250 consecutive cases.
OBJECTIVE: To evaluate the role of intraoperative cytology (IC) in the improvement of diagnostic accuracy obtained by frozen section (FS) alone. STUDY DESIGN: Comparison of 2,250 intraoperative cytologies performed along with frozen sections, with the final diagnoses achieved on paraffin sections. RESULTS: In 18 cases the diagnoses were deferred until the paraffin sections at the time of intraoperative consultation. The diagnostic accuracy in distinguishing benign from malignant lesions by combined intraoperative cytology and frozen section was 99.2%. The accuracy rate is significantly higher than that reported in large series based on frozen section preparations alone. Sensitivity and specificity were, respectively, 98.2% and 100%. The diagnostic accuracy of each technique alone was 94.9% for FS (sensitivity 89.9%, specificity 97.9%) and 96% for IC (sensitivity 94.9%, and specificity 96.8%). Although specific diagnoses were more frequently formulated on the bases of frozen section examination, FSs were not diagnostic in 113 case in which cytology allowed a specific diagnosis. CONCLUSION: Our results emphasize the increasingly important diagnostic role of intraoperative cytology as an adjunct to frozen section. The approach does have limitations.
Breast Neoplasms↗
The role of instrumental diagnostic methods in the staging of Sudeck's disease.
Forty patients with Sudeck's atrophy were assessed in order to evaluate the diagnostic accuracy of x-ray, scintigraphy and telethermography in staging the 3 phases of the disease. The dynamic and early static phases of scintigraphy were the most sensitive and specific instrumental tests for detecting the early stage, whereas telethermography was fairly sensitive but not very specific. Radiographic examination was not sensitive in detecting slight changes in bone density, but it was the most reliable index for recognizing the transition to stage II of the disease. Moreover, it was possible to confirm that the late static phase of scintigraphy is the index which is best related to bone metabolism.
Adult↗
Advanced diagnostic methods in oral and maxillofacial pathology. Part II: immunohistochemical and immunofluorescent methods.
The practice of pathology is currently undergoing significant change, in large part due to advances in the analysis of DNA, RNA, and proteins in tissues. These advances have permitted improved biologic insights into many developmental, inflammatory, metabolic, infectious, and neoplastic diseases. Moreover, molecular analysis has also led to improvements in the accuracy of disease diagnosis and classification. It is likely that, in the future, these methods will increasingly enter into the day-to-day diagnosis and management of patients. The pathologist will continue to play a fundamental role in diagnosis and will likely be in a pivotal position to guide the implementation and interpretation of these tests as they move from the research laboratory into diagnostic pathology. The purpose of this 2-part series is to provide an overview of the principles and applications of current molecular biologic and immunologic tests. In Part I, the biologic fundamentals of DNA, RNA, and proteins and methods that are currently available or likely to become available to the pathologist in the next several years for their isolation and analysis in tissue biopsies were discussed. In Part II, advances in immunohistochemistry and immunofluorescence methods and their application to modern diagnostic pathology are reviewed.
Antigens, Neoplasm↗
Comparison of diagnostic methods in the diagnosis of dermatomycoses and onychomycoses.
Direct microscopic examination of potassium hydroxide (KOH)-prepared specimens is the simplest, cheapest method used for the diagnosis of mycotic infections of the skin. However, KOH preparations have been reported to have 5-15% of false-negative results, possibly because of the low visibility of scant, scattered fungal material of the nail scrapings and because the detection of fungal elements depends on the skill of the observer [Arch Dermatol133 (1997) 1317; Clin Microbiol Rev8 (1995) 240]. We compared two different KOH-based staining methods in order to obtain reliable results in shorter time than expected for cultures. A total of 124 patients with suspect diagnosis of dermatomycosis or onychomycosis were enrolled. Two scrapings from the same lesion of each patient were stained with KOH-Chlorazole and KOH-Acridine Orange (AO), respectively; cultural examination of the same specimen was considered as diagnostic gold standard. The two methods showed neither significantly different sensitivity nor specificity; however, for onychomycoses, we observed a slightly higher sensitivity for KOH-Chlorazole and a higher specificity for KOH-AO. We suggest the use of both techniques in order to improve detection of fungal infection, especially for onychomycoses.
Acridine Orange↗
[Rapid diagnosis of infectious endophthalmitis using polymerase chain reaction (PCR): a supplement to conventional microbiological diagnostic methods].
BACKGROUND: Endophthalmitis is, although relatively rare, a serious intraocular infection, which could result in a loss of visual function. Therefore, the rapid diagnosis and initiation of the appropriate treatment is of critical importance. To date, approximately 60 percent of eyes with a clinical diagnosis of infectious endophthalmitis show a positive microscopic or culture result. By using the very sensitive polymerase chain reaction this number might increase. PATIENTS AND METHODS: In a series of 12 eyes with infectious endophthalmitis we have performed microscopic investigations, diagnostic culture and polymerase chain reaction in aqueous humor and vitreous in order to detect the infectious agent. RESULT: Microscopic investigations showed a positive result in the vitreous of 3 eyes. This number improved to 6 eyes using culture media. Significant less positive results were obtained in the aqueous humor. The infectious agent could be detected in the aqueous humor in all 12 eyes and in the vitreous in 9 eyes by PCR. Only in 2 eyes with a delayed endophthalmitis the vitreous was negative. CONCLUSIONS: The detection of the infectious agents was more successful using PCR compared to conventional microbiological tests. In particular, for the diagnosis of delayed endophthalmitis PCR proves to be very superior. In all cases of delayed endophthalmitis the pathogen could be detected in the aqueous humor.
Aqueous Humor↗
[Various diagnostic methods in the examination of vascular exophthalmous].
The radiological examination results are reported form 13 cases of vascular exophthalmos in the presence of carotid-cavernous sinus fistels, carotid aneurysm and vascular malformations of the orbit. The results of the various methods of examination in the literature are discussed and proposals are suggested for a consequent diagnostic procedure.
Adolescent↗
Percutaneous peritoneal lavage in blunt trauma patients: a safe and accurate diagnostic method.
We reviewed the records of 395 patients seen from January 1983 through May 1988, who after sustaining blunt thoracoabdominal trauma had diagnostic peritoneal lavage (DPL) performed percutaneously by the Seldinger wire technique of Lazarus and Nelson. The test was considered grossly positive if 10 cc of blood were aspirated from the catheter immediately after its insertion into the peritoneal cavity. Microscopic criteria for positivity included more than 100,000 RBC or 500 WBC/cc of lavage return, elevated amylase or bilirubin, or the presence of vegetable fibers or bacteria. Seventy-two (18%) of the patients were true positives and 315 (80%) were true negatives. There were four false positives (1.3%) and one false negative (0.2%), giving the test a sensitivity of 99% and a specificity of 98%. Complications occurred in three patients, for a rate of 0.8%, and included catheter insertion into a large ovarian dermoid cyst, needle perforation of the ileum, and needle perforation of the sigmoid colon. This technique of DPL can consistently be performed much more rapidly than the open method. Therefore we conclude that percutaneous DPL is as accurate as, as safe as, and quicker than open DPL for determining intra-abdominal injury in blunt trauma patients.
Abdominal Injuries↗
[Acute infections caused by Epstein-Barr virus. Comparative study of various diagnostic methods].
Comparative performance of four methods (IFI, IgM anti-VCA, Organon Teknika; ELISA, IgM anti VCA, Incstar Corp and Pharmacia Diagnostic Inc; ELISA IgM against a group of several antigens which principal component is EBNA, Behring Institute) to detect antibodies (Abs) against Epstein-Barr virus in 180 patients (group 1) with infectious mononucleosis with no heterophil Abs (Organon Teknika), 180 healthy subjects with no heterophil Abs (group 2) and 20 patients with infectious mononucleosis (group 3) and with positive heterophil Abs, were studied. In group 1, 10% of patients had IgM Abs, without differences IgM Abs. In group 3 all patients had IgM Abs with no differences in the methods studied. There were no differences in the performance of the evaluated methods to detect IgM against different antigens, but those which use a group of antigens from the virus could be more useful in patients immunologic disorders.
Adolescent↗
Value of present diagnostic methods for gastrointestinal nematode infections in ruminants.
In this paper the different options for the diagnosis of gastrointestinal nematode infections are discussed. Diagnostic tests have a role in confirming the clinical diagnosis of parasitic gastroenteritis, but are more important for herd health monitoring of nematode infections, in particular for cattle. Therefore, emphasis is placed on discussing the available diagnostic parameters on their usefulness for that purpose. For clinical diagnosis the clinical signs, combined with the history of the animals is usually sufficient and a laboratory confirmation is not required. Faecal egg counts are, with two exceptions, not suitable for confirmation of the clinical diagnosis, because correlation between faecal egg counts and infection levels is usually low. These exceptions are the diagnosis of haemonchosis in small ruminants and the detection of anthelmintic resistance. This also limits the value of DNA-based tests of faecal material; even quantitative tests of nematode species specific DNA will have little value for diagnosis and monitoring. Pasture larval counts and worm counts are useful parameters for basic epidemiological studies on nematode infections. However, they are too laborious to be used for either routine diagnosis or monitoring. Blood parameters, such as gastrin and pepsinogen and serology are valuable tools for diagnosis. Pepsinogen and ELISAs based on recombinant proteins show most promise as parameters for herd health monitoring. However, extensive epidemiological studies are still needed before these parameters can be implemented in routine herd health monitoring schemes for parasitic gastroenteritis.
Animals↗
Characterization and validation of diagnostic methods.
Diagnosis is defined as the determination of disease, but not as the determination of the signs and symptoms thereof. The use of modern diagnostic methodology in the clinic is hampered by cost considerations and by the still widespread belief that, e.g. caries lesions and periodontal breakdown are irreversible processes that need to be detected and treated invasively as early as possible, their measurement thus being irrelevant. Modern instrumental and quantitative methods allow early detection and introduction of noninvasive preventive measures to control the development of the disease. Such methods are also very beneficial in clinical research as they may describe the speed of progress or regress of disease. In epidemiology, such methods reduce the classical problem of calibration of observers. Repeatability, reproducibility, accuracy and validity are defined as method-characterizing quantities, for which examples are given. To express the validity of quantitative methods compared with a quantitative gold standard, the use of scatter plots and correlation and regression methods is suggested. Validation of a dichotomous method with a dichotomous gold standard in terms of sensitivity and specificity is discussed. To validate a quantitative method with a dichotomous gold standard, the receiver operating characteristic curve is suggested, with the requirement that the cutoff value should be determined in relation to the use of the method. However, preferably a quantitative method should not be reduced to a dichotomous one by using a cutoff value, but instead all available information should be used by the diagnostician. It is argued that the use of a secondary standard instead of the accepted gold standard usually leads to inadequate results, even when the validity of the secondary standard is known. Finally, it is argued that the choice of a gold standard is a matter of reasoning and weighing of arguments and not of following a prescribed procedure.
Calibration↗
[Comparison of the cost-effectiveness of the most common diagnostic methods for coronary artery disease].
BACKGROUND AND OBJECTIVE: The cost-effectiveness of medical procedures is becoming a crucial factor besides their efficacy in clinical decision-making. We performed a cost-effectiveness analysis of the most common diagnostic modalities used in assessing coronary artery disease (CAD). METHODS: A decision tree model for determining the cost-effectiveness in CAD diagnosis was applied to the situation in Germany to calculate the cost-effectiveness of exercise ECG (ExECG), stress echocardiography (ECHO), myocardial scintigraphy (SPECT), and coronary angiography (ANGIO). The cost-effectiveness was defined as direct and induced costs per correctly identified patient. A sensitivity analysis was performed varying the predictive accuracies, the complication-related costs, and costs and complication rates of ANGIO. RESULTS: The costs per correctly identified patient decreased in a hyperbolic fashion as the pretest likelihood of CAD increased due to the higher incidence of positive findings. For a pretest likelihood between 10 and 40%, ExECG and ECHO were most cost effective with costs per CAD patient of 5,880 - 2,500 EUR and 6,410 - 2,280 EUR, respectively. The combination of ExECG und ECHO (application of the second modality in case the first one was nondiagnostic) further improved the cost-effectiveness up to a pretest likelihood of 35%. For a pretest likelihood of 50% or greater, ANGIO costing 1,880 - 940 EUR per correct diagnosis was most cost-effective. Sensitivity analysis revealed no significant changes demonstrating the robustness of the model. CONCLUSION: ANGIO is the most cost-effective procedure for a pretest likelihood of 50% or greater. At lower pretest likelihoods, ExECG, ECHO and the combined ExECG/ECHO strategy based on economic considerations are the preferred modalities for diagnosis of CAD.
Cohort Studies↗
The lung in the immunocompromised host: diagnostic methods.
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Biopsy, Needle↗
[Some diagnostic methods in diseases of the mediastinum].
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Bronchoscopy↗
Etiologic agents, incidence, and improved diagnostic methods of cantharidin toxicosis in horses.
In addition to the 3-striped blister beetles (Epicauta temexa and E occidentalis), other sources of equine cantharidin toxicosis were identified at the Texas Veterinary Medical Diagnostic Laboratory and included E albida and E attrivittata and the previously incriminated E pardalis and E pennsylvanica. Improved methods for diagnosing cantharidin or blister beetle toxicosis involve partial purification of urine and gastric content extracts, using silica cartridges, followed by analysis, using capillary gas chromatography/mass spectrometry. During a 26-month period, 53 episodes of cantharidin toxicosis in horses were confirmed at our diagnostic laboratory. Concentrations of cantharidin in urine and gastric contents ranged from 0.0003 to 3.50 micrograms/g. Peak incidences were observed in late summer and early fall.
Animals↗
[Selective kidney angiography. Indispensable diagnostic method in urogenital tuberculosis].
Selective angiography of the kidneys was performed in 119 patients with urogenital tuberculosis. The diagnosis was confirmed by bacteriological and/or histological examinations. Diagnostic value. Under optimal technical conditions changes of the small renal arteries even in the parenchymal stage I of renal tuberculosis can be seen. These cannot be diagnosed with other methods. In stage II and III the degree of destruction and the localisation of the specific process can be demonstrated more efficiently by angiography than by urogram. In stage III/3 (kidney without function) the differential diagnosis between tuberculosis and the late form of polycystic renal disease is possible. Therefore the selective renal angiography ought to be performed more frequently for intensive diagnosis and also to reach a definite diagnosis before surgical procedures. Special surgical planning is more precise and knowledge of vascular anatomy reduces the operative risk.
Diagnosis, Differential↗
[Detection of patent foramen ovale. Transesophageal echocardiography and transcranial Doppler sonography with ultrasound contrast media are "supplementary, not competing, diagnostic methods"].
BACKGROUND: The prevalence of patent foramen ovale (PFO) in healthy individuals is estimated to be about 25% and is elevated to 40% patients with stroke. To date transesophageal echocardiography (TEE) was considered to be the most sensitive method to detect PFO and was regarded as the gold standard. Transcranial Doppler sonography of the middle cerebral artery during contrast injection (c-TCD) has recently been proposed as an alternative method for the detection of PFO. We report our experience on 45 patients (age < 55 years) with stroke or transient ischemic attack (TIA) in whom both c-TCD and TEE were performed to detect PFO as a mechanism for embolic cerebral ischemia. PATIENTS AND METHODS: In 45 patients (21 women, 24 men, mean age 41.4 years ranging from 17 to 54 years) with cerebral ischemia, both standardized TEE and standardized c-TCD were performed separately. When any PFO was found by TEE and/or c-TCD, it was classified as positive. If c-TCD was positive but TEE negative, a second TEE was performed and vice versa. RESULTS: PFO was found epicritically in 26 patients (57.8%). First TEE detected PFO in 24 cases (sensitivity 92.3%). Separately performed c-TCD detected PFO in 22 cases of the PFO-positive cases (sensitivity 84.6%). However, c-TCD detected PFO in 2 cases, in which the first TEE had been negative, leading to a second TEE which confirmed PFO and demonstrated minimal shunt (7.7%). TEE detected PFO in 4 cases in which first c-TCD was negative. A second c-TCD confirmed in 2 of these 4 cases a positive right-to-left shunt. Neither method revealed false positive results (specifity 100%). The positive predictive value was 100% in both methods. The negative predictive value in TEE was 90.5% and in c-TCD was 82.6%. CONCLUSION: TEE and c-TCD are not concurrent diagnostic tools to detect PFO. Both supplement each other. If both methods are used in all PFO-suspected patients, PFO detection rate is higher than when using either method alone.
Adolescent↗