PubMed · 7271544
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H P Schmitt. 1981. Internalized capillaries.. https://doi.org/10.1001/archneur.1981.00510090095017
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Raynaud's phenomenon is a common paroxystic vasomotor disorder. Diagnosis is easily made based on white fingers caused by cold. Aetiological evaluation must distinguish between functional disorders (primary Raynaud's phenomenon or Raynaud's disease) and secondary Raynaud's phenomenon. Initially, physical examination as well as nailfold capillary microscopy are sufficient for the diagnosis of bilateral Raynaud's phenomenon. Prescription of other investigations is guided by the results of this first evaluation. Progressive systemic sclerosis is the first hypothesis if the bilateral vasomotor disorder does not satisfy the criteria for primary Raynaud's phenomenon. Unilateral Raynaud's phenomenon is much less common and always secondary to local or regional vascular disease. Treatment of Raynaud's phenomenon must be adapted to the level of discomfort and to the cause of the vasomotor disorder. Prescription of drugs must be restricted to the most serious cases.
OBJECTIVE: To compare blood lead (BPb) poisoning screening strategies in light of the 1997 recommendations by the Centers for Disease Control and Prevention, Atlanta, Ga. DESIGN: Cost-effectiveness analysis from the perspective of the health care system to compare the following 4 screening strategies: (1) universal screening of venous BPb levels; (2) universal screening of capillary BPb levels; (3) targeted screening of venous BPb levels for those at risk; and (4) targeted screening of capillary BPb levels for those at risk. Costs of follow-up testing and treatment were included in the model. RESULTS: Only universal venous screening detected all BPb levels of at least 0.48 micromol/L (10 microg/dL). Universal capillary screening detected between 93.2% and 95.5% of cases, depending on the prevalence of elevated BPb levels. Targeted screening was the least sensitive strategy for detecting cases. Venous testing identified between 77.3% and 77.9% of cases, and capillary testing detected between 72.7% and 72.8% of cases. In high-prevalence populations, universal venous screening minimized the cost per case ($490). In low- and medium-prevalence populations, targeted screening using venous testing minimized the cost per case ($729 and $556, respectively). In all populations, regardless of screening strategy, venous testing resulted in a lower cost per case than capillary testing. Sensitivity analyses of all parameters in this model demonstrated that this conclusion is robust. CONCLUSIONS: Universal screening detects all cases of lead poisoning and is the most cost-effective strategy in high-prevalence populations. In populations with lower prevalence, the cost per case detected using targeted screening is less than that of universal screening. The benefit of detecting a greater number of cases using universal screening must be weighed against the extra cost of screening. Regardless of whether a strategy of universal or targeted screening is used, the cost per case using venous testing is less than that of capillary testing.
OBJECTIVE: To test whether a method of fingerstick blood sample collection onto filter paper could be used as an alternative screening method in the field in settings where environmental lead contamination is a high risk. METHOD: Members of the Pediatric Mobile Team of Children's Hospital of Michigan, Detroit, collected paired venous and capillary blood samples from 120 children, aged 6 months to 6 years, who presented for services at any of 7 sites located in decaying neighborhoods of older sections of Detroit. All samples were analyzed for lead content by graphite furnace atomic absorption spectrometry. RESULTS: When filter paper samples with blood lead levels of 0.48 micromol/L (10 microg/dL) or higher were compared with matched venous samples, the concordance coefficient was 0.96. The sensitivity and specificity of the filter paper samples relative to the venous samples for a cutoff of 0.48 micromol/L (10 microg/dL) or higher were 94% and 99%, respectively, with a positive predictive value of 97%. However, at a cutoff of 0.72 micromol/L (15 microg/dL), the sensitivity and specificity dropped to 75% and 98%, respectively, with filter paper samples underreporting blood lead values. At any cutoff point (0.48, 0.72, or 0.96 micromol/L [10, 15, or 20 microg/dL]), the filter paper method was highly specific for lead. CONCLUSIONS: Capillary filter paper sampling is an accurate and practical alternative to venous sampling for blood lead screening using 0.48 micromol/L (10 microg/dL) as the cutoff. The filter paper method predicts levels of 0.72 micromol/L (15 microg/dL) or higher less well. The cause of divergent values above 0.72 micromol/L (15 microg/dL) is not clear. Environmental contamination of capillary filter paper, however, does not seem to be an explanation.