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PubMed2001

[Laboratory diagnosis of hepatitis C].

Laboratory algorithm for the diagnosis of viral hepatitis C (HVC) is proposed. Blood sera are screened for antiHVC by third-generation EIA and PCR of HVC RNA. Positive result of PCR is diagnostically significant. In case of positive EIA and negative PCR the serum is to be analyzed in immunoblotting. If immunoblotting is not carried out, the diagnosis is made on the basis of estimated values of hepatitis C probability attached to diagnostic EIA kit used in clinical laboratory. When evaluating the positive result, the increase in optic density (OD) of analyzed samples is compared with the cutoff OD. In OD higher than 9 and below 1.5 the probability of disease is 92.6 and 11.8%, respectively. Patients with doubtful results of serological tests are to be regularly checked up for 1 year, with laboratory tests (immunoblotting and PCR) repeated every 3 months. Complex laboratory diagnosis by biochemical and serological methods and PCR should be carried out in groups at a high risk of HVC.

Hepacivirus↗
PubMed1989

[Epidemiologic aspects of the laboratory diagnosis of streptococcal infections].

Current status and prospects of laboratory diagnosis of streptococcal infections are analyzed. Available investigation schedules and methods for the detection and identification of Streptococcus pyogenes are assessed in epidemiologic terms. The importance of early laboratory diagnosis of first instances of disease is emphasized. Laboratory tests for streptococcal infection are an important element of prompt epidemiologic evaluation. They are to provide a preventive action rather than state fully-developed epidemics of scarlet fever or angina, as practiced currently. Approaches to the determination of the group and type of the causative agents are assessed critically. Additional investigation methods are presented and described.

Humans↗
PubMed1990

[A proposed method for the laboratory diagnosis of disseminated intravascular coagulation in liver cirrhosis].

Laboratory diagnosis of disseminated intravascular coagulation (DIC) in liver cirrhosis (LC) could be complicated by the presence of the usual decrement of the hemocoagulative parameters and of an increase of the fibrinogen/fibrin degradation products (FDP). The D-dimer test, more sensible than the one for FDP and specific for the cross-linked fibrin degradation products is now available. A significant difference between the two tests, assayed simultaneously has been demonstrated in 217 LC patients, without any recent or present hemorrhagic signs. The D-dimer was increased in only 60 of the 108 patients with high values of FDP; therefore this test has a screening value higher than FDP. If only the D-dimer is elevated, the FDP assay is indicated: if FDP are normal a thrombosis may be present and, finally, if the FDP are also increased with a concomitant decrement of fibrinogenemia, the laboratory diagnosis of DIC is reasonably certain.

Adult↗
PubMed1989

[Experience in attracting co-workers at a department of clinical laboratory diagnosis to diagnostic and therapeutic work].

The experience gained by the Lvov City Clinical Hospital for Emergencies evidences the usefulness of participation of the workers of clinical diagnosis chairs in practical diagnostic and therapeutic work, for it considerably reduces the number of diagnostic errors. The authors consider such cooperation between practicing physicians and laboratory workers (many of them are not physicians) very useful and recommend to change the system of training in laboratory diagnosis at specialized and advanced training courses so that the number of physicians working at clinical diagnosis laboratories be increased.

Laboratories, Hospital↗
PubMed1991

[Laboratory diagnosis in HIV infection].

The laboratory diagnosis of an HIV infection is mainly based on the detection of antibodies. Many reliable tests are commercially available. Although they have excellent characteristics (sensitivity and specificity above 99%), their positive predictive value is low in populations with a very low prevalence of HIV infections. Therefore, reactive screening tests must be validated by a confirmatory test in order to reduce the probability of false positive results to an acceptably low level, i.e. below 1%. The detection of HIV by cell culture, antigen detection or genome detection is less standardized and, as a single test, less sensitive than the antibody tests. It is useful as an additional investigation in cases where the results of antibody tests are equivocal.

AIDS Serodiagnosis↗
PubMed1981

Laboratory diagnosis of animal mycoplasma infections.

Laboratory diagnosis of animal mycoplasma infections is generally based on isolation of the mycoplasmas from the diseased tissues, followed by biochemical and serological identification of the isolates. However, the presence of serum antibodies and the demonstration of circulating antigen or antigen in infected lung tissue has also proved invaluable in the diagnosis of contagious bovine pleuropneumonia. The isolation of a particular mycoplasma from a diseased tissue does not necessarily imply a causal relationship. It is important to know the pathogenicity potential of the mycoplasma in question, the number of mycoplasmas present, the presence of any other potentially pathogenic microorganisms and any other relevant information before the role of the mycoplasma can be assessed and a diagnosis of mycoplasma infection given.

Animals↗
PubMed1997

Laboratory diagnosis of Cyclospora infections.

The laboratory diagnosis of newly recognized infectious agents, such as Cyclospora cayetanensis, is frequently problematic because appropriate diagnostic techniques and algorithms are not available. The methods currently available for diagnosis of Cyclospora are described and compared, including concentration procedures, examination of wet preparations, various staining techniques, and the use of molecular-based assays. Because of the autofluorescent properties of the oocysts, particular attention is drawn to the role of fluorescent microscopy in providing a rapid, inexpensive, and sensitive technique for diagnosis of Cyclospora infections in stool samples. In addition to text descriptions, photomicrographs are provided to illustrate Cyclospora oocysts in wet and stained preparations and compare them with Cryptosporidium and Isospora oocysts, the other two most common coccidian infections in man.

Animals↗
PubMed1991

[Computer-assisted laboratory diagnosis].

A theory of laboratory data-based diagnosis and results of its application are reported. The diagnosis was made by linear discriminant analysis and matrix analysis, and the two diagnostic modalities were tested in healthy subjects and patients with 10 different diseases of the liver and the biliary tract. The optimal number of test items to be incorporated in the discriminant for screening was 2 to 3 in liver parenchymal diseases but tended to be 4 to 5 or more in obstructive or space-occupying diseases. A newly designed matrix discrimination was applied to this evaluation. By this method, all healthy individuals could be discriminated from patients. A mean percentage of 97.5% (92-100%) of patients with liver parenchymal diseases could be discriminated by the first 2 variables, and a mean of 86.2% (71-98%) of those with obstructive or space-occupying diseases could be discriminated by the first 3 variables. The basic architecture and function of a quantitative diagnostic system for screening of diseases of the liver and the biliary tract, which we are developing on the basis of this matrix discrimination method, are outlined with our prospects of computer-assisted laboratory diagnosis.

Biliary Tract Diseases↗
PubMed1988

Use of murine monoclonal antibodies for laboratory diagnosis of varicella-zoster virus infection.

The laboratory diagnosis of varicella-zoster virus (VZV) infection was reevaluated by direct immunofluorescent-antibody staining (DFA) and centrifugation culture with newly available murine monoclonal antibodies. Specimen smears were examined by DFA using monoclonal antibodies to VZV and to herpes simplex virus types 1 and 2. Specimens were also inoculated into shell vials for centrifugation culture and into standard tube cell culture. Of 68 specimens tested from 60 patients, 39 (57%) were positive for VZV by at least one method. DFA was positive in 36 of 39 (92%); centrifugation culture was positive at 24 h in 23 of 39 (59%) and at 48 h in 31 of 39 (79%); and standard culture was positive in 25 of 39 (64%). Twenty-three of the 39 positive specimens (59%) were positive by all three techniques. Forty-three of the 60 patients were considered to have VZV by clinical criteria, and 35 of these 43 (81%) had laboratory confirmation of the diagnosis. These data confirm that DFA is the method of choice for the rapid laboratory confirmation of VZV infection. The centrifugation culture assay can provide an alternative method to DFA for the laboratory diagnosis of VZV infection.

Animals↗
PubMed1997

Improved laboratory diagnosis of ovine footrot: an update.

Ovine footrot is a complex clinical disease syndrome primarily resulting from infection by the anaerobic bacterium Dichelobacter nodosus. In order to aid clinical diagnosis, various laboratory tests based on the detection and measurements of phenotypic properties of D. nodosus have been developed for genus-specific detection as well as virulence determination. However, these tests are generally time-consuming, and tend to be variable with external factors that affect the growth and metabolism of the bacterium. A new generation of diagnostic reagents, such as monoclonal antibodies, gene probes and polymerase chain reaction, has been developed recently. Preliminary assessment of these reagents has shown potential to vastly improve the laboratory identification and determination of the virulence of D. nodosus. It is important that these new reagents are vigorously assessed against existing laboratory tests, such as the elastase test and gelatin gel test, prior to their adoption for the routine diagnosis of footrot.

Animals↗
PubMedDate not supplied

The laboratory diagnosis of tuberculosis in a period of resurgence: challenge for the laboratory.

OBJECTIVE: To review the current and contemporary approaches to the laboratory diagnosis of Mycobacterium tuberculosis and related mycobacteria. DATA SOURCES: Current literature. STUDY SELECTION: Determined by the author. DATA EXTRACTION: Determined by the author. DATA SYNTHESIS: The definitive diagnosis of mycobacterial disease depends upon the laboratory for the isolation and identification of the infecting microorganism. Laboratory studies encompass microscopic examination for the presence of AFB; isolation and recovery of the organism by cultural methods; phenotypic biochemical or other contemporary means to identify the recovered organism; and anti-tuberculosis susceptibility testing. Because of the extended growth period of this group of organisms, it is imperative that the lab use the most rapid means to provide information to the clinician for isolation of the patient if needed and for the initiation of prompt rational therapy as determined by susceptibility testing. More than 25 species in the Mycobacterium genus are capable of causing human disease. In the United States, the five most frequently encountered species are M. tuberculosis, M. avium, M. kansasii, M. fortuitum and M. chelonei. CONCLUSION: Tuberculosis is a reemerging disease with significant health problem implications in the US and worldwide. Diagnosis and appropriate treatment are dependent on the prompt response of the laboratory.

Bacteriological Techniques↗
PubMed2004

[Rapid laboratory diagnosis of tuberculosis in clinical practice].

The laboratory diagnosis of tuberculosis relies on direct microscopy of smears for acid-fast bacilli and culturing. Microscopy is a rapid, but neither sensitive nor specific diagnostic method. Cultivation on solid media is a time-consuming procedure, and isolation and identification of Mycobacterium tuberculosis takes 3-8 weeks. Introduction of new selective liquid media with a sensitive growth-detection system, dramatically decreased time necessary for isolation and susceptibility testing, so that positive results can be obtained in two weeks. However, wide use of these systems is limited by high cost of instruments and media. Nucleic acid amplification techniques have in recent years been introduced in clinical laboratories for diagnosis of tuberculosis. Amplification techniques are highly sensitive and specific, and positive results are available in a few hours. Nevertheless, molecular methods cannot replace culturing, when drug susceptibility testing is required.

Humans↗
PubMed1977

[The laboratory diagnosis of amoebic infections in man (author's transl)].

The rapid progress made in both theoretical and practical fields in laboratory medicine, in general, and in microbiological diagnostic procedures, in particular, have also led to a significant enlargement of, and improvement in laboratory diagnosis of amoebic infections in man. In all intestinal infections with Entamoeba histolytica the demonstration of the parasite is absolutely essential, but is facilitated nowadays by the great improvement in technical conditions. Immunodiagnostic methods have become of great importance in all cases of extraintestinal manifestation of parasite. By the combined application of several serological tests (latex test + indirect haemagglutination test or latex test + indirect immunofluorescence test) practically 100% of cases of extraintestinal amoebiasis can be detected. When using all available optimum methods of laboratory diagnosis today, it is neither possible to overlook an infection with Entamoeba histolytica nor to make a flase positive diagnosis. Great difficulties are still encountered in the laboratory diagnosis of primary meningoencephalitis caused by free-living amoebae of the Limax group owing to the dramatic course of the disease. Present and possible future methods are discussed.

Amebiasis↗
PubMed1969

Diabetes mellitus--current criteria for laboratory diagnosis.

Among the laboratory methods and test procedures used for the diagnosis of diabetes mellitus in clinical practice, the oral glucose tolerance test, if performed properly, remains the cornerstone in the definitive diagnosis of diabetes. The intravenous glucose tolerance or the tolbutamide response tests may be indicated especially when there is a question of proper oral carbohydrate assimilation. The value of the cortisone-glucose tolerance test is still in question. Insulin assays may be helpful in differentiating between the various types of diabetes. Accepted criteria for normal and abnormal values for all tests are tabulated.

Clinical Laboratory Techniques↗
PubMed1997

Laboratory diagnosis of anemia and related diseases using multivariate analysis.

To establish a simple computer program for the laboratory diagnosis of anemia and related diseases, multivariate analyses were applied to the results of routine hematological laboratory tests obtained from 48 patients and 51 healthy volunteers. The patients studied were limited to those who had not been treated hematologically by the time of their first visit to our hospital, and their first data obtained in our laboratory were analyzed. Final diagnoses were aplastic anemia (AA) in 21, myelodysplastic syndrome (MDS) in 14, iron deficiency anemia (IDA) in 3, polycytemia vera (PV)in 3, and idiopathic thrombocytopenic purpura (ITP) in 7. Eight parameters, WBC, RBC, Hb, Ht, MCV, MCH, MCHC, and PLT, were transformed to normal distribution and then applied to principal component analysis to evaluate their independence. Very close relationships were observed between Ht and Hb, and between MCV and MCH. One each of these pairs was selected by discriminant analysis and two sets, RBC, MCH, Hb, PLT, and WBC, and RBC, MCV, Ht, PLT, and WBC, were obtained. Two canonical components gave good discrimination of these five diseases and also of normal subjects. When disease prediction was made using this analysis, 37 of 48 patients (77.1%) were predicted correctly, and furthermore, when two disease predictions were allowed, all patients were diagnosed properly. Some overlaps were observed in this two-dimensional coordinate system, especially of AA and MDS, and also with normal subjects. To improve the system further, the additional parameters of age and sex were added to construct a three-dimensional analysis which resulted in much clearer discrimination. The whole procedure described is being developed with subjects who are not taking medication. Subsequently, the general application of this analytical procedure should be limited to only those not on medications. In conclusion, this is in essence a demonstration project; however, this trial of laboratory diagnosis using routine hematological laboratory results appears to be promising. Further extension of the study by increasing numbers of patients and disorders studied, including secondary anemias, will allow the design of diagnostic software for use with personal computers at the sites of primary care.

Adult↗
PubMedDate not supplied

Laboratory diagnosis of thrombophilic states: where do we stand?

Until recently the laboratory diagnosis of thrombophilia consisted on investigation of the plasmatic anticoagulant pathways and the search for dysfibrinogenemia and antiphospholipid antibodies/lupus anticoagulants. More recently, the laboratory investigation has been expanded by including activated protein C (APC) resistance, due or not to the presence of the factor V Leiden mutation; hyperprothrombinemia, due to the presence of the prothrombin mutation G20210A and hyperhomocysteinemia, due to impairment of the relevant metabolic pathway because of enzymatic and/or vitamin deficiency. Testing for thrombophilia may be useful for many reasons. First, the results of testing may provide valuable information to assess the risk of recurrence in the proband. Second, testing family members is useful for prophylactic and diagnostic purposes. Third, the identification of patients bearing combined defect helps to identify those at increased risk for thrombosis. Testing is recommended for patients with a past history of thrombosis and should be extended to their first-degree family members. Since most of the tests are not reliable during anticoagulation, it is preferable to postpone laboratory testing until after discontinuation of the treatment. Whenever possible testing should be performed by means of functional assays. DNA analysis is required for the prothrombin mutation G20210A. Laboratory diagnosis for antiphospholipid antibodies/lupus anticoagulant should be performed by a combination of tests including phospholipid-dependent clotting assays and solid phase anticardiolipin antibodies. Hyperhomocysteinemia may be assessed by high-pressure liquid chromatography methods, or by fluorescence polarization immunoassays.

Hematology↗