Critical appraisal of the pattern of antinuclear antibodies (ANA) testing requested over a six month period at the "Escola Paulista de Medicina" (EPM), São Paulo.

In order to evaluate the pattern of ANA testing solicitation, 506 patients with ANA testing requested from July 1st. 1988 to December 31st, 1988, had their charts reviewed. These patients, randomly selected, were regularly attending the outpatient clinic at the "Escola Paulista de Medicina" (EPM). 289 patients were followed up at the Rheumatology Division (group A) and 217 patients at other clinical divisions at EPM (group B). The diseases that most frequently motivated the request for ANA test were: group A--SLE (22.5%), RA (18.0%), undefined arthropathies (6.2%), PSS and CREST (5.9%) and Raynaud phenomena (5.5%); and group B--rheumatic diseases (24.4%), nephropathies (17.1%), neuropathies (16.6%), dermopathies (7.8%), hemopathies (4.6%), pneumopathies (4.2%) and ophthalmopathies (3.7%). The positivity of ANA test in groups A and B was 32.9% and 17.5% respectively. 94 SLE patients were clinically diagnosed. The positivity of ANA and anti-dsDNA tests in this group was respectively 85.1% and 26.6%. The sensitivity and specificity of 1982 ARA revised criteria were 94.7% and 99% respectively. The likelihood ratio (LR) of a positive or a negative test was established for this population. LR of a positive test was 6.5 while for a negative test it was 0.17. The ANA test, although lacking specificity, has been commonly requested by different specialties in order to practically rule-out the diagnosis of some connective rheumatic diseases. Immunofluorescence technique (IF) using antibodies conjugated with fluorochromes. was first described by Coons et al. in 1941. This method has been used as an important diagnostic tool in routine laboratory tests ever since.(ABSTRACT TRUNCATED AT 250 WORDS)

Critical study of the effect of temperature on total serum complement determination

Basic rules establish that the total serum complement determination (CH50) should be done after quick serum separation at 4 degrees Celsius. When there is a long period between blood sample collection and laboratory tests, the results may not be exact, with findings being below normal level due to thermolability and dysfunction of some of the components. Sera from 15 normal individuals and 15 patients with Systemic Erithematous Lupus (SEL) were studied. CH50 determinations were performed by the radial immunohemolysis technique according to the above basic rules and compared to determinations performed after 4, 8, 12 and 24 h in sera maintained at room temperature and after 24 h in those maintained at 4 degrees Celsius. Five samples (2 controls and 3 lupoid) were stored at -2O degrees Celsius and -7O degrees Celsius. CH50 determinations were performed weekly in sera kept at -2O degrees Celsius and after l month in those stored at -7O degrees Celsius. Analysis of the results suggest that, if blood samples are kept at room temperature and the determination is performed within about 8 h, the results are still reliable, that is, they will be within normal levels. The same will happen if the sera are stored at -2O degrees Celsius or -7O degrees Celsius for up to l month.

[Rhabdomyosarcoma: unusual aspects]. / Rabdomiossarcoma: aspectos inusitados.

The authors report a case of embryonal rhabdomyosarcoma with several interesting aspects which make it difficult to diagnose.