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At least 1,135 records · Page 63Linked to original sources
PubMed1994

Laboratory diagnosis and occurrence of Pneumocystis carinii.

Pneumocystis carinii is an opportunistic pathogen causing life threatening pneumonia (PCP) in immunosuppressed patients and particularly among AIDS patients. Whether the infection results from reactivation or reinfection is debated. Since methods for in vitro cultivation still are not successful, the diagnosis is dependent on direct demonstration of the organism in respiratory specimen. In this thesis laboratory diagnostic methods in terms of staining, sampling, antibody detection and DNA amplification are evaluated. Furthermore, the occurrence of the organism in the Western world versus Africa, and in symptomatic and asymptomatic HIV infected patients is studied and discussed. The use of a monoclonal antibody (MAb), 3F6 in an indirect immunofluorescence assay (IFL) was compared to the two most commonly used chemical stains, silver methenamine and toluidine blue. The IFL method detected both cyst and trophozoite stages of P. carinii and was more sensitive than the chemical stains when applied to sputum samples. Among commercialised MAbs for P. carinii detection by IFL, only the indirect tests were readily applicable to ethanol treated HIV inactivated samples. In contrast to the MAb 3F6, (Dakopatts), the MAb from Northumbria stained only a selection of the cysts and no trophozoites. The relative sensitivity of IFL in detecting the organism in sputum samples compared to bronchoalveolar lavage (BAL) samples was estimated to be at least 70%. The polymerase chain reaction (PCR), which can amplify specific DNA fragments, was used for the demonstration of P. carinii in sputum and BAL specimens. The PCR was shown to be specific and more sensitive than IFL. However, P. carinii DNA was found in a few patients without clinical evidence of present, past or future PCP. Thus the possibility of PCR to detect colonization must be considered. Detection of antibodies to P. carinii by indirect IFL was studied in HIV versus non-HIV patients. A titer rise was seen in 45% of non-HIV patients versus only 3% in HIV patients during a PCP episode. No humoral response was seen in AIDS patients, whereas the serology did support the clinical PCP diagnosis in a proportion of the otherwise immunosuppressed patients. Serology may however not be of help in the acute setting. In the beginning of 1988 PCP had not yet been reported from Central Africa where the AIDS epidemic by then was growing fast. The occurrence of P. carinii in Central Africa was evaluated by a comparative study on induced sputum samples from HIV infected patients with pulmonary infection in Stockholm, Sweden and Lusaka, Zambia.(ABSTRACT TRUNCATED AT 400 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1976

Laboratory diagnosis of urinary tract infection in children.

One-third of the total number of 1,500 urine specimens examined each month by the bacteriology department of the Royal Children's Hospital, Melbourne, originate in the General Paediatric Clinic. The patients, presenting with acute symptoms, are similar to those encountered in general practice. This article discusses the laboratory methods used to support a diagnosis of urinary tract infection (UTI) in childhood.

Bacteriological Techniques↗
PubMed2001

Laboratory diagnosis of acute myeloid leukaemia.

The modern characterization of acute myeloid leukaemia is a multidisciplinary process. It requires the integration of clinical information, morphology, cytochemistry, immunophenotyping, cytogenetic and molecular genetic diagnostic techniques. It is only by bringing all these modalities together that a clear picture of the disease can be presented. This initial work-up provides essential prognostic information of benefit to the patient. The selection of treatment and the monitoring of treatment response are dependent on the findings at the time of diagnosis.

Acute Disease↗
PubMed2000

Factor VIII inhibitors. Laboratory diagnosis of inhibitors.

The diagnosis of inhibitors of blood coagulation is often the most challenging problem in the clinical laboratory. Immediate attention must be given to the following patient groups whose principal laboratory abnormality is the prolonged activated partial thromboplastin time (aPTT): the patient with (1) hemophilia who previously responded to an adequate dose of clotting factor product and now fails to show effective clinical response to the same replacement concentrate; (2) previously benign clinical history who now presents with soft tissue bleeding or emergent internal hemorrhaging; (3) sudden onset of generalized ecchymoses who was previously well; (4) postpartum state; (5) malignancy, lymphoma, rheumatoid arthritis, or other autoimmune disorders; and (6) drug reactions. Immediate attention must be given to the prolonged prothrombin time (PT), aPTT, and thrombin time (TT) in order to respond to urgent queries from a perplexed internist, hematologist, intensivist, or surgeon caring for a patient with unexpected bleeding. Sometimes the problem of a prolonged "clotting time" arises preoperatively, causing unanticipated delay in operative procedures. For this reason, the laboratory support, usually in the coagulation section of a clinical laboratory or reference laboratory, must be quick, unequivocal and precise. The most common finding is an isolated mild, moderate, or severe prolongation of the aPTT with a normal PT, TT, and platelet count. The aPTT mixing study (The Mix), usually modified for time and temperature, along with appropriate controls, is the seminal test. This is the basis for all further testing. It may be supported by direct factor assays, and, therefore, the laboratory must know the reagent responsiveness and sensitivity for each clotting factor. By definition, complete correction of the aPTT in a 1:1 mix of patient and reference plasma is a factor deficiency. In this article, incomplete or minimal correction of The Mix will be characterized with particular attention to the various inhibitor assays, in other words, Oxford, Bethesda, and Nijmegen assays and the enzyme-linked immunosorbent assay (ELISA). An investigative approach to final characterization of the intensity (quantification) of the inhibitor and the exclusion of a lupus anticoagulant (LA) will be discussed.

Blood Coagulation Tests↗
PubMed1994

Routine laboratory diagnosis of continuous ambulatory peritoneal dialysis peritonitis using centrifugation/lysis and saponin-containing media.

This study examines the application in a routine laboratory of a method for concentrating and lysing leucocytes in continuous ambulatory peritoneal dialysis (CAPD) effluent to diagnose peritonitis. Between November 1986 and April 1990 pathogens from 42 of 82 (51%) CAPD specimens from patients with acute peritonitis failed to grow on horse blood agar (HBA) after direct inoculation. Recovery rates of pathogens were 74% (6 of 82) from a solid medium containing saponin and 89% (73 of 82) after lysing the leucocytes before inoculating HBA. Microbial sequestration in leucocytes was demonstrated in 73% (60 of 82) of specimens, while pathogens from 11% (9 of 82) were grown only from a liquid medium. Thirteen of 17 specimens with < 500 leucocytes/mm3 grew on all three solid media. Gram stain microscopy revealed organisms in 51% (41 of 81) of specimens. The method, using apparatus and media prepared for everyday examination of specimens, is sensitive, specific and yields single colonies of most species within 24 h.

Adolescent↗
PubMed1982

Laboratory diagnosis in a large outbreak of type A botulism: confirmation of the value of coproexamination.

Coproexamination is a vital component of the laboratory evaluation of botulism and is an essential part of the investigation of suspected botulism cases. In April 1978, type A botulism developed in 34 persons who had eaten at a restaurant in a town in New Mexico. Pretreatment serum specimens, along with stool specimens for toxin assay and culture for Clostridium botulinum, were obtained. At least one specimen (serum or stool) was available for each patient. Of 30 serum specimens, 16 (53%) were toxin positive; seven (32%) of 22 stools were toxin positive; and C. botulinum type A was cultured from 19 (79%) of 24 stool specimens. Overall laboratory confirmation was available for 26 cases (76%). Serum and stool toxin detection was related both to the time elapsed between symptom onset and specimen collection and to the severity of illness, with shorter times and severe illness associated with higher rates of toxin detection. Recovery of C. botulinum type A did not vary appreciably according to these factors. In 18 cases, both serum and stool specimens were available; the proportion of suspected cases that could be laboratory-proven increased by 46% when patients' feces, and not just their sera, were subjected to botulism testing procedures.

Adolescent↗
PubMed1992

[Capillary blood as diagnostic sample in pediatric laboratory diagnosis. Arterio-capillary-venous difference and blood collection technique].

It is preferable to use capillary blood as diagnostic material in paediatric laboratory tests rather than venous blood. The collection of capillary blood makes less demands on the child and is easy in principle. The objection to capillary blood primarily concerns differences in the analyte concentration in arterial, capillary and venous blood. Comparative studies in the same child under standardised conditions are not available for a number of parameters. However, according to the results available at present, for almost all routine clinical chemical and haematological examinations clinically usable results can be obtained. Using the example of total protein analysis for the same child we did not find any differences between arterial and venous blood. It is highly probably that the same would apply to many other components. Suspected differences are probably a result of short-comings in the collection technique.

Blood Chemical Analysis↗
PubMed1994

Practical considerations in the laboratory diagnosis of bacterial enteric infections.

Diarrheal diseases caused by bacterial pathogens are important causes of morbidity in the United States, and considerable laboratory resources are spent to detect these enteric pathogens. This article reviews recent developments in the detection and identification of Campylobacter spp, enterohemorrhagic Escherichia coli, and Clostridium difficile, and outlines cost-effective strategies for use of stool cultures.

Bacterial Infections↗
PubMedDate not supplied

[Value of laboratory diagnosis in thrombolytic therapy].

Today, profound insight into the clotting and fibrinolytic systems during therapeutic thrombolysis is offered by a variety of laboratory assays. While the purpose of scientific investigations is to increase the knowledge on changes imposed by the mechanism of thrombolysis, the rationale for performing coagulation assays during thrombolytic therapy is to increase the safety of treatment. To make laboratory monitoring of thrombolytic therapy most effective, the main issues which should be solved should be defined. The main reasons for performing coagulation assays during and after thrombolytic therapy are: 1. To monitor the adjunctive anticoagulant therapy. 2. To detect potential bleeding hazards early, and 3. in case bleeding complications occur, to help to optimise of the therapeutic strategies to avoid excessive diagnostics. Most of the methods affording an insight into coagulation and fibrinolysis are not very helpful in terms of improved therapeutic safety. Too frequent repetition of assays is likewise superfluous. In our opinion, clinical routine monitoring should consist of red blood cell count, aPTT, and fibrinogen according to Clauss' method which should be repeated during the first 48 hours after initiation of therapy at 8- to 12-hour intervals. It must be mentioned in this respect that fibrinogen according to Clauss' method during thrombolytic therapy must be regarded an assay to estimate the global coagulation potential of the blood rather than to quantify fibrinogen levels. In our opinion, it is this that makes the Clauss' method superior to other methods of fibrinogen determination.

Blood Coagulation Tests↗
PubMed1977

[Laboratory diagnosis and internal medicine. Introduction].

The development of internal medicine went parallel with the clinico-chemical diagnostics. The increase of the laboratory achievements, also in the field of prevention, is possible by a regional graduation of the laboratories with a centralisation as effective as possible under management of specialists. It is referred to the observation of quality instructions in standardized methods. The improvement of diagnostics by exchange between clinic and laboratory is particularly emphasized.

Clinical Laboratory Techniques↗
PubMed1997

[Laboratory diagnosis in iron deficiency anemia].

The diagnosis of iron deficiency is based, in first line, on clinical and hematological findings. Clinical-chemical laboratory investigations lend support to these findings, and may also provide differential diagnostic information. In particular with respect to the question whether an iron deficiency or an iron distribution disorder is presenting, clinical-chemical parameters can be of value. For the diagnosis of an iron deficiency and for the evaluation of the iron metabolism as a whole, determination of ferritin, transferrin and iron is adequate.

Anemia, Iron-Deficiency↗
PubMed2005

[Potentialities of laboratory diagnosis in tuberculous meningitis].

The results of examination of 84 patients with tuberculosis of the central nervous system were used to make comparative clinical and laboratory studies. They revealed that lymphocytosis detected in the cerebrospinal fluid (CF), particularly the prevalence of lymphocytes (more than 50%), and decreased levels of chlorides in the cytogram were of value in the comprehensive diagnosis of tuberculous meningitis. The detection of CF Mycobacterium tuberculosis (MBT) (applying the whole currently available set of methods) is an absolute criterion for the diagnosis of tuberculous meningitis (however, with, unfortunately, few number positive results). The detection of mycobacterial DNA, antigens, and tuberculosis antibodies is an impotent component of a diagnostic complex for tuberculous meningitis. The determination of cytosis, protein, glucose, chlorides, lymphocytic subpopulations, soluble gamma-interferon mediators, mycobacteria, DNA, MBT antigens, and tuberculosis antibodies in SF is essential in treating tuberculous meningitis.

Adolescent↗