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PubMed2002

UV-visible spectrophotometric approach to blood typing II: phenotyping of subtype A2 and weak D and whole blood analysis.

BACKGROUND: A recently introduced quantitative blood typing approach uses antibody-induced changes in the UV-visible spectra of blood. Changes in the blood spectra's slope, caused by RBC agglutination, are translated into a numerical agglutination index (AI). Comparing the AI value against an established threshold yields a "yes and/or no" output from which to determine the phenotype. The efficacy and flexibility of this approach with whole blood use and the ability to analyze weak D, A2, and A2B were examined. STUDY DESIGN AND METHODS: Two hundred randomly selected blood bank donor samples were coded and forward typed directly from whole blood by using the spectrophotometric analysis. Reverse grouping on plasma from each sample was carried out with a new modified procedure by using higher ratios of plasma to RBCs. Results were compared to typing by an FDA-cleared automated typing system. Twenty-seven weak D samples, 15 A2 and 12 A2B, were similarly analyzed from whole blood. PEG improved detection of weak D, A2 and A2B subtypes. RESULTS: All two hundred coded samples were accurately typed, yielding identical results to the blood bank analysis in both forward and reverse grouping. All the weak D samples and A2 and A2B samples were clearly identified, having AIs above the type threshold indicator value. CONCLUSION: Spectrophotometric blood typing successfully phenotyped ABO and D in 200 whole blood samples. Reverse grouping of plasma was equally successful. The same method can identify weak D and A2 and A2B subtypes.

ABO Blood-Group System↗
PubMedDate not supplied

Comparison of a miniaturized culture test and sheep blood agar for the recovery of Group A streptococci from throat cultures.

A miniaturized culture test (strep test) was compared with conventional sheep blood agar (SBA) for the detection of Group A streptococci (GAS) from throat swabs. A total of 355 throat cultures were obtained in duplicate from symptomatic children and assessed by the two methods after overnight incubation. GAS were detected in 109 specimens by the strep test, in 100 specimens by SBA and in 118 specimens by both methods. There was no significant difference between the recovery rate of GAS by the strep test (92.4%) and SBA (84.7%) (0.1 greater than P greater than 0.05). The strep test was 85.2% specific for detection of GAS. The rates of false positive and false negative reactions with the strep test were 24.3 and 4.3%, respectively. Beta-hemolytic streptococci other than Group A, Staphylococcus aureus and alpha-hemolytic streptococci produced false positive reactions. The viability of GAS on the strep test was also tested. GAS were recovered from 27 of 28 (96.4%) strep tests at 24 hours and 25 of 27 (92.6%) tests at 72 hours after inoculation. These results indicate that strep test is as sensitive as the conventional SBA method in recovering GAS. The strep test is simple to use, is easy to interpret and has a long shelf life. Because of the high rate of false positive results (24.3%), this test may not be the best alternative method to SBA for use in office practice.

Agar↗
PubMed1999

Preoperative clinical radioimmunodetection of pancreatic cancer by 111 In-labeled chimeric monoclonal antibody Nd2.

The present study was carried out with the purpose of evaluating the clinical usefulness of radioimmunodetection (RAID) with 111In-labeled murine/human chimeric monoclonal antibody, Nd2 (c-Nd2) in patients with pancreatic cancer. Nineteen patients suspected to have pancreatic cancer were administered intravenously 74 MBq/2 mg 111In-labeled c-Nd2 in 100 ml of saline containing 2% albumin over 30 min. A scintigram was obtained on the 3rd day after infusion by using single photon emission computed tomography (SPECT) imaging. Of the 14 patients finally diagnosed as having pancreatic cancer on the basis of surgical specimens or progress of disease, specific focal uptake at the site of the tumor was detected in 12 (true positive cases), representing a sensitivity of 85.7% (12/14), and liver metastasis was found in one case with metastasis. Of the 5 patients diagnosed with tumor-forming pancreatitis (TFP), 4 patients demonstrated true negative imaging, but one patient whose tumor demonstrated interesting findings in histology and immunostaining, showed false positive imaging. Of patients investigated for human anti-chimeric antibody (HACA) response, none showed HACA response, and no allergic reaction was seen in any of the patients administered c-Nd2. These results suggest that RAID with 11In-labeled c-Nd2 is useful for differential preoperative diagnosis between invasive pancreatic cancer and TFP.

Aged↗
PubMed1997

Misdiagnosis of cancer due to multiple glove powder granulomas.

A biologically absorbable powder, the cornstarch lubricant used in the production of gloves, is treated with epichlorohydrin, a cross-linking agent forming one to three diether glycerine groups to create a glove lubricating powder. This agent, together with chemicals used in glove fabrication is able to interfere with important biological diagnostic procedures, such as polymerase chain reaction (PCR) and enzyme immunoassay as well as to induce a granulomatous reaction in traumatised surgical tissue.

Absorption↗
PubMed1989

The polymerase chain reaction, a review of the practical limitations for human immunodeficiency virus diagnosis.

The polymerase chain reaction (PCR) is a powerful method for the in vitro amplification of specific nucleic acid sequences. As very small amounts of a virus genome can be detected it has obvious diagnostic applications. The background to the reaction and its use for human immunodeficiency virus (HIV) detection are described. The problems likely to be encountered in using PCR as a diagnostic assay (false positives and negatives) and the practical measures which can be taken to overcome them are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Detection of residual disease in acute lymphoblastic leukemia of childhood.

Several techniques developed in recent years provide us with the capability to detect sub-microscopic leukemia during remission. Quantitative polymerase chain reaction (PCR) is thus far the most sensitive assay that is applicable in most patients with acute lymphoblastic leukemia (ALL) of childhood. However, false-positive and false-negative results may provide the clinician with misleading data and therefore PCR analysis should be accompanied by another assay and changes in the level of residual disease should be confirmed at different time points following treatment. Furthermore, several studies did not determine a threshold of residual disease level above which relapse is likely to occur, and more recent data show that long-term remission may be sustained in the presence of residual disease. Thus, additional studies of the biology of residual disease in childhood ALL should be performed before sensitive assays of residual disease detection and quantitation can be clinically utilized.

Animals↗
PubMedDate not supplied

Evaluation of three enzyme immunoassays for HIV-1 antigen detection.

Three enzyme immunoassay (EIA) methods for the detection of human immunodeficiency virus (HIV-1) were evaluated. Serum or plasma samples from 22 individuals seropositive for HIV-1 antibodies were tested with the Abbott, Coulter, and DuPont kits for presence of HIV-1 p24 antigen. Another 12 samples were tested with two kits only. Discordant results were obtained with 9 of 34 (26%) HIV-1-antibody-positive patient samples tested. Most of these discrepancies were found in samples containing less than 30 pg/ml of HIV-1 p24 core antigen. A sampling of sera from normal blood donors and patients with infectious or autoimmune diseases revealed a low level of false positive reactions, especially with sera containing antinuclear antibodies or rheumatoid factor. Noteworthy is the frequency of false positive reactions seen with the DuPont EIA for HIV-1 p24 antigen. 18/111 sera (16.2%) containing auto-antibodies tested positively with the DuPont HIV-1 p24 antigen EIA. The nonspecific nature of the test reactivity for 9/10 of these samples was confirmed using an HIV-1 p24 antigen inhibition assay. These findings are discussed in light of the need for HIV-1 antigen detection in the clinical laboratory and of other methods for HIV-1 detection: the polymerase chain reaction and measurements of reverse transcriptase activity.

Evaluation Studies as Topic↗