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Evaluation of a laboratory system intended for use in physicians' offices. I. Reliability of results produced by trained laboratory technologists.

The accuracy and precision of the Kodak DT-60 tabletop chemistry analyzer were evaluated in the clinical laboratory at the Portland (Ore) Veterans Administration Medical Center, and its operational throughout and cost were estimated. All DT-60 tests that were studied exhibited clinically acceptable precision and, except for the glucose method, accuracy. The accuracy of the glucose method was indeterminate with the available data. Throughput under field conditions was found to be less than half of the manufacturer's claim. The estimated supply cost per test could vary from $1.20 to $5.49 per test, depending on the test type and the number of assays expected to be performed daily. The instrument seems to be accurate, precise, and generally reliable when operated by professional medical technologists.

Autoanalysis↗

Bringing HELP to the clinical laboratory--use of an expert system to provide automatic interpretation of laboratory data.

In domains where the types of data which are to be interpreted are relatively constrained (as in the case of specific laboratory test results), our modular data-driven approach can be very productive and well received by the clinical recipient of the data. The computer rarely surpasses the knowledge of an experts result from lack of communication, imperfect memory, oversight or multiple decision-makers caring for the same patient. In such cases, most of the alerts are immediately recognized as valid, so the need for elaborate explanations is not a high priority. On the other hand, a non-specialist is alerted to the need for additional investigation, tests or collaborative support, by the fact that a reminder or diagnosis that s/he had not previously considered, appears. In other words, for the expert, a data-driven system provides unceasing oversight in high-volume low-yielded situations where a small number of mistakes may uncommonly occur for reasons which are not related to the lack of knowledge of the provider. For the non-specialist the system suggests that the patient may have problems in a domain for which the physician needs additional support. In the present state of the art, we do not think that total reliance on the computer-contained knowledge is the ultimate source of this additional support; providing the awareness of the need may be the most important contribution. Once you know that you need help, it is usually obtainable. In a discussion about how computer systems have failed, Friedman and Gustafson made the following observation.(ABSTRACT TRUNCATED AT 250 WORDS)

Decision Making, Computer-Assisted↗

[Difference of some laboratory findings between investigations in medical practice and the clinical laboratory].

Report about some spermatograms of a patient which were investigated in an andrological practice as well as in a clinical special department. There exist many differences especially concerning the sperm motility, sperm density and finally the autoagglutination of spermatozoa. It is not possible to explain these differences in detail, but it is to emphasize that a careful training of the technicians could be the best guarantee for successful work in a laboratory. Furthermore the intralaboratory control as well as the interlaboratory control should better be used.

Humans↗

[Effect of drugs on laboratory diagnosis--effect of propranolol on selected laboratory values].

In the accessible literature the influence of beta-blockers on laboratory methods is estimated only little systematically and nearly exclusively on parameters of the glucose and lipometabolism. The influence on several methods in vitro is without relevance to practice. Own examinations showed that in 32 patients with essential hypertension of stage I (after Baumann and Nitschkoff) under therapeutic doses of 50--80 mg propranolol a day in none of the 18 chemical parameters tested after a four weeks' treatment significant deviations relevant to practice appeared in comparison to the parameters before treatment.

Adolescent↗

FRAR course on laboratory approaches to aging. Genetic quality control in laboratory rodents.

Laboratory rodents are widely used in gerontological research. Many different strains are available, and superficially there is little to distinguish them (many are albino), although they may differ markedly in life span and pattern of spontaneous disease, as well as for a whole range of biochemical, immunological, behavioural and physiological characteristics. As experience has shown that strains can easily become muddled, some form of genetic quality control is essential. There is no single method of genetic quality control which can be recommended for all occasions. Methods based on identification of Mendelian genetic markers, such as biochemical and immunological polymorphisms can be sensitive, but may be expensive and require considerable expertise. Methods based on simultaneous study of several markers, such as skin grafting and polyvalent strain-specific antisera, may be cheaper but less flexible. DNA fingerprinting and the use of microsatellite markers appear to be the methods of choice in the future, though these are still expensive and require considerable expertise.

Animals↗

[Derivation of latent reference intervals from routine laboratory database: its principle, validity and methodological implications for laboratory informatics].

A new method to derive reference from routine laboratory database intervals was developed. It depends on (1) availability of multiple screening tests results, (2) initial estimates for the reference intervals (RI) and (3) exclusion of data with multiple abnormalities in "related" test items. We designated those data which remained after exclusion as "latent reference values". RI was calculated from them parametrically employing a modified Box-Cox power transformation and maximal likelihood method. After RI were derived for all the items, they were used as a new set of RI estimates and the series of exclusion/calculation procedures were repeated for 7 times. The validity of the latent reference intervals (LRI) derived from routine biochemical screening test results were evaluated in three ways, by comparing them (1) with RIs determined conventionally from healthy individuals, and (2) with LRIs derived from qusi-normal individuals (blood donors), and (3) with LRIs obtained from a simulated healthy population which was generated as multivariate normal random values.

Adult↗

[Clinical laboratory diagnosis and aging. 1: Results of data evaluation of clinico-chemical laboratory values in a study of aging].

The results of the determination of 24 basic blood chemistry variables from 262 men and 239 women, half of each group 44.4 +/- 0.9 and 63.0 +/- 0.9 (men) and 44.4 +/- 0.9 and 62.8 +/- 0.8 years old (women), resp., are compared. In men, only 6 analytes show significant differences between the age groups: Alanine aminotransferase decreases, aspartate aminotransferase decreases, iron decreases with p < 0.05; sodium increases, calcium decreases, protein (serum) decreases with p < 0.001. In women, 16 analytes, compared between both groups, are significantly different: Urea, uric acid, creatinine, triglycerides, total cholesterol, LDL cholesterol, LDL-C/HDL-C ratio, alanine aminotransferase, alkaline phosphatase, gamma-glutamyltransferase, sodium and ferritin are increased in the older group, whereas HDL cholesterol, iron, transferrin, and total protein are decreased. The sex differences are more distinct in the group of 44 years old persons than in the 63 years old one. These results will be completed by the comparison with the evaluation of the stored laboratory values of 9923 patients between 20 and 89 years old.

Adult↗

Platelet storage solution affects on the accuracy of laboratory tests for platelet function: a multi-laboratory study.

BACKGROUND AND OBJECTIVES: Extent of shape change (ESC) and hypotonic shock response (HSR) have been widely used to characterize the in vitro function of platelets and have been shown to correlate with in vivo viability. These assays have been routinely performed using platelet-poor plasma (PPP) as the test sample diluent. Because of the increasing popularity of storing platelets in synthetic media, it is important to understand the effects of using these synthetic media as test diluents for ESC and HSR measurements. The objective of this study was to determine the effect of using platelet storage solutions vs. plasma for the in vitro testing of ESC and HSR. MATERIALS AND METHODS: Six laboratories participated in this study. Platelets were prepared by apheresis, the platelet-rich plasma (PRP) method, or derived from buffy-coats. Each platelet preparation was divided, half being stored in plasma and the other half in storage solution. ESC and HSR testing were performed in duplicate on days 1 and 5, using each of three diluents: autologous plasma; fresh-frozen plasma; or storage solution. RESULTS: For both ESC and HSR, dilutions made in each of the three diluents yielded significantly different results. Dilutions made in storage solutions were more than 30% lower for ESC and HSR than those made in autologous plasma (P < 0.0001). Dilutions made in thawed fresh-frozen plasma were more than 16% lower for ESC and HSR than those made in liquid autologous plasma (P < 0.0005). CONCLUSIONS: ESC and HSR test results are significantly affected by the test diluent. Platelets should be diluted in plasma (preferably autologous) for the in vitro testing of ESC and HSR, regardless of the media in which they are stored.

Blood Platelets↗

Laboratory tests in the detection of extended spectrum beta-lactamase production: National Committee for Clinical Laboratory Standards (NCCLS) screening test, the E-test, the double disk confirmatory test, and cefoxitin susceptibility testing.

Extended spectrum beta-lactamase (ESBL) production by Klebsiella sp. and E. coli is an emerging problem. In this study, 107 clinical isolates (53 E. coli, 47 K. pneumoniae and 7 K. oxytoca) screened as ESBL producers by the NCCLS disk diffusion procedure were submitted to a double disk confirmatory test (DDT) and to the E-test double strip for confirmation of ESBL production by demonstration of clavulanic acid inhibition effect (CAIE). Only 72/107 (67%) of the isolates were confirmed as ESBL producers by DDT, with diverse results among species. By the E-test, 58/107 (54%) isolates were confirmed as ESBL producers, and 18/107 (17%) were not determinable. Susceptibility to cefoxitin was found in 57/68 (83%) of strains that did not show CAIE. ESBL detection remains a controversial issue and clinical laboratories are in need of a simple and effective way to recognize strains with this kind of resistance.

Anti-Bacterial Agents↗

Circular on prenatal examinations of unborn children in the laboratories of public hospital establishments and in clinical laboratories, 12 April 1988.

This Circular is addressed to the French regional and departmental authorities responsible for health and social affairs. It clarifies the present situation regarding the prenatal diagnosis of certain defects or serious or fatal deformations of the fetus. It specifies the reasons for regulation of this field and defines the conditions in which a prenatal diagnosis may be carried out in the public and private sectors. Various annexes are appended providing, among others, a standard form for the record of the prenatal diagnosis and the list of laboratories carrying out prenatal diagnoses of chromosome defects drawn up on 1 March 1988.

Chromosome Aberrations↗

Origin of the v. portae and variability of its tributaries in laboratory animals. III. The laboratory rat (Rattus norvegicus var. alba).

The authors studied the origin of the v. portae and the variability of its tributaries in 30 adult laboratory rats (Rattus norvegicus v. alba) after injecting blue-dyed latex into the venous bed. In 21 cases (70.0%) the v. portae was formed from three tributaries. In 18 of these cases (60.0%) they were the v. mesenterica cranialis, v. lienalis and v. pancreaticoduodenalis cranialis. In eight cases the v. portae was formed from four or five tributaries and in only one case was it formed from two--the v. mesenterica cranialis and v. lienalis. In 21 cases (70.0%) the v. gastrica sinistra was a tributary of the v. lienalis. It collected blood from the anterior and posterior surface of the stomach and sometimes originated as far away as the curvatura major ventriculi. A v. cardiaca was present in all 30 cases (100%). As a rule (in 28 cases, i.e. 93.3%), it was a tributary of the v. gastrica sinistra. There was likewise a v. pylorica in every case; most frequently this united with the v. pancreaticoduodenalis cranialis, but was also connected with other veins in the vicinity. A v. pancreaticoduodenalis cranialis was always present. In 22 cases (73.3%) it was an independent tributary of the v. portae. In 11 cases (36.7%), there were no vv. gastroepiploicae or equivalent vessels and blood from the stomach was drained mainly by the v. gastrica sinistra. A v. gastroepiploica dextra was present in 11 cases (36.7%), mostly as a tributary of the v. lienalis; in two cases (6.7%) there was a v. gastroepiploica sinistra and in six cases (20%) the place of these veins was taken by vv. gastricae as tributaries of the v. lienalis. In 21 cases (70.0%) the v. lienalis was joined by the v. gastrica sinistra. In 22 cases (73.3%) inter-organ anastomoses between the spleen, stomach and pancreas were found. A v. pancreaticoduodenalis caudalis was always present and in 20 cases (66.7%) it was an independent tributary of the v. mesenterica cranialis. A comparison of the origin of the v. portae and the organization and variability of its tributaries in the rat, cat and guinea pig shows that, in agreement with their position in the zoological system and their mode of life, there was greater similarity between the rat and the guinea pig as regards practically all the veins examined.

Animals↗

The medical laboratory scientist in the clinical chemistry service laboratory.

The recent opening of an official register for medical laboratory scientists in South Africa has prompted an examination of the professional role, training and qualification of one particular group of scientists, namely clinical chemists working in hospital pathology departments. Lack of recognition of the potential contribution of these non-medical graduates towards improved health care, together with the lack of facilities for their professional advancement, has hitherto inhibited the growth and development of clinical chemistry in this country. An urgent need is the local establishment of a specialist postgraduate qualification open to the non-medical clinical chemist.

Chemistry, Clinical↗

[Evaluation of external laboratory test results for the correct identification and determination of chemotherapeutic sensitivity of staphylococci in bacteriologic provincial laboratories of sanitary-epidemiologic stations in 1995].

In the tests bacteriological laboratories participated in 45 sanitary-epidemiological stations. Each station was given two strains of staphylococci: S. epidermidis and S. aureus homogeneously resistant to methicillin (MRSA) or S. aureus sensitive to methicillin (MSSA), and S. aureus coagulase-negative and clumping-factor-positive strain. The analysis was carried out of the results of control identifications of strains of the determinations of the sensitivity of the identified strains to antibiotics. Among the studied strains the greatest difficulty in identification were caused by the coagulase-negative strain of S. aureus. In the determination of the sensitivity of the control strains to chemotherapeutic agents abnormalities were found in the technique of antibiogram performing and incorrect selection of discs for antibiograms as well as erroneous interpretation of the results.

Methicillin↗