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Biomedical subjects

David F Keren

Publications and source records attributed to David F Keren.

9 recordsLinked to original sources
PubMed2005

Serum free light chain (FLC) measurement can aid capillary zone electrophoresis in detecting subtle FLC-producing M proteins.

We hypothesized that using a free light chain (FLC) assay as an adjunct to capillary zone electrophoresis (CZE) could improve detection of lymphoplasmacytic processes. We prospectively studied 1,003 consecutive serum samples submitted for routine protein electrophoresis and/or immunofixation electrophoresis by CZE and FLC. Samples from patients previously characterized as having M proteins were excluded. Protein electrophoresis was read by a pathologist unaware of the FLC results. Sixteen cases revealed an abnormal free kappa/lambda ratio in which CZE did not demonstrate an M protein. Nine cases of B-lymphocyte or plasma cell proliferative processes were detected by an abnormal free kappa/lambda ratio in which CZE did not demonstrate an M protein. Cases with low free kappa/lambda ratios included 1 chronic lymphocytic leukemia (CLL), 1 IgM lambda with aplastic anemia, and 1 lambda light chain myeloma. Cases with high free kappa/lambda ratios included 2 CLL, 1 lymphocytosis (possibly early CLL), 1 kappa light chain myeloma, 1 atypical lymphoma with neuropathy, and 1 nonsecretory myeloma. Addition of the free kappa/lambda ratio to CZE increases the yield of lymphocyte and plasma cell proliferative processes detected by 56%.

Aged↗
PubMed2002

Antinuclear antibody testing.

The ANA test is an excellent screening test for patients with SLE and a few other connective tissue diseases. The LE cell preparation is an assay that is subjective and costly. Because of the presence of a superior screening test (the ANA) and superior specific auto-antibody tests, the author recommends that the use of LE cell preparations be discontinued. ANA screening tests may be performed either by indirect microscopic serology (usually IFA) or EIA. The latter technique is readily automated and many new products for this screening test have appeared in the past decade. The products differ, however, and laboratories are cautioned to test each in the context of the clinical needs of their clinicians. Proper use of the ANA test requires each laboratory to determine the cutoff used under their conditions of assay. Although either ANA screening test has a high negative predictive value in numerous studies, proper selection of patients to be tested is key to improving the predictive value of a positive result. The American College of Rheumatism criteria are reviewed and recommended as part of the patient selection process for this testing.

Antibodies, Antinuclear↗
PubMed2002

Comparison of murex single-use diagnostic system with traditional enzyme immunoassay for detection of exposure to human immunodeficiency virus.

Because a retrospective study detected 13 negative Western blots out of 38 single-use diagnostic system (SUDS)-positive cases over a 1-year period, we performed a prospective study to compare the performance of the SUDS test with that of enzyme immunoassay (EIA). Of 888 SUDS-tested sera, 875 (98.4%) were both SUDS and EIA negative and 5 (0.6%) were SUDS, EIA, and Western blot positive. The rate of SUDS-positive samples decreased from 3.16/month in the retrospective study to 1.33/month in the prospective study. The immunoassays had sensitivities and specificities of 100 and 99.7 (SUDS) and 100 and 99.4% (traditional EIA), respectively. In laboratories with experienced personnel, the SUDS test performs as well as the EIA as a screen for infection with the human immunodeficiency virus.

Blotting, Western↗