Determination of reference values for serum folate and vitamin B12 using three different immunoassays: is it worth making an effort to produce them in our laboratory?

BACKGROUND: Despite being a widely studied concept, the reference interval is the most widely used medical decision-making tool. As such, it is vital that these limits are correctly established and regularly reviewed in the clinical laboratory. METHODS: The reference population comprised 315 healthy individuals selected a priori from Bizkaia province. Blood and serum samples were sent for subsequent assay of vitamin B12 and folate using three immunochemical methods. Reference values were calculated using non-parametric methods. RESULTS: The reference values for serum vitamin B12 and folate were almost identical to those obtained previously using the same methods. Use of new reference values led to an increase in the kappa value despite the low agreement in the case of vitamin B12 (0.4 - 0.62). However, precision obtained for vitamin B12 (94.48 - 96.55%) and folate (95.77 - 97.18%) was very high. The intraclass correlation coefficient ranged from 0.723 to 0.894. Furthermore, a Passing-Bablok regression analysis gave acceptable correlation coefficients of 0.75 - 0.94 for vitamin B12 and 0.92 - 0.95 for folate. CONCLUSIONS: Vitamin B12 and folate deficiencies are currently being over-diagnosed leading to an increase in the number of unnecessary consultations. The main conclusion that can be drawn from our study has resulted in a change in reference values in our laboratory, with a subsequent increase in our ability to accurately detect possible deficiencies. Furthermore, as this study involved all methods currently in use in the Basque healthcare network, its conclusions can be extrapolated to the whole population covered by Osakidetza, thereby improving the rational use of healthcare funding.

[Prevalence of tobacco use among teenagers and its relation with family environment]. / Prevalencia del consumo de tabaco en adolescentes. Influencia del entorno familiar.

OBJECTIVE: To determine the prevalence of tobacco use among 12-18 year-olds in Biscay (Spain) and its relation with the family environment. SUBJECTS AND METHOD: We performed a cross-sectional study in 12-18 year-olds. A self-administered, anonymous questionnaire was distributed in different schools of the region selected by stratified sampling, based on the type of school (public school or subsidized private school) and on the linguistic model. The final study sample comprised 1921 students. Information was obtained on tobacco, alcohol and other drug use, as well as on family and sociodemographic characteristics. RESULTS: A total of 51.8 % of the students had used tobacco. One-third (29.9%) of the teenagers were current smokers and 50.4% were daily smokers. The mean age of first tobacco use was 13.1 +/- 1.85 years. The prevalence of tobacco use was higher in girls and increased with age until the age of 15-16 years. More than 90 % of smokers had experimented with alcohol, 86.3 % had used cannabis at some time and 11 % had used other illegal drugs. In multivariate analysis, the variables associated with a higher odds of smoking were age, female sex, available money, use of other drugs, and smoking by siblings in front of the adolescent. CONCLUSIONS: The prevalence of tobacco use among 12-18 year-olds increased in relation to female gender, age, having siblings who smoked in their presence, available money, and the use of alcohol, cannabis and other illicit drugs. Maternal and sibling disapproval of smoking may be associated with lower tobacco use among adolescents.

[Tuberculosis among immigrants in Bilbao (Spain)]. / Tuberculosis en la población inmigrante de Bilbao.

OBJECTIVE: To assess the prevalence of tuberculosis (TB) and latent tuberculous infection among immigrant residents of Bilbao who came from countries where the disease is highly prevalent. We also studied related social and health conditions. MATERIAL AND METHODS: A descriptive study carried out in the San Francisco neighborhood of Bilbao. Subjects were enrolled during a seven-month period by a social worker and by the personnel of a non-governmental organization (Médicos del Mundo) who recruited volunteers from among persons requesting medical or social assistance. The subjects who agreed to participate answered systematic questionnaires on social and medical conditions and were given tuberculin tests and chest X-rays. RESULTS: We initially evaluated 406 immigrants (mean age 32.5 years; SD 9.7) mainly from sub-Saharan Africa, 83.2% of whom were undocumented. Three hundred six completed the study (75.4%). Compliance was higher among those who applied for medical certificates (p = 0.039) or who were symptomatic (p = 0.016). Thirty-one subjects had been exposed and 0.83% had active TB. CONCLUSION: We believe that TB screening tests for recently arrived immigrants are necessary given the high rate of exposure and disease. Incentives and the cooperation of non-governmental organizations could improve acceptance of and compliance with such programs.

[Clinical and epidemiological spectrum of Mycoplasma pneumoniae infections at a pediatric hospital]. / Espectro clínico-epidemiológico de las infecciones por Mycoplasma pneumoniae en un hospital infantil.

OBJECTIVE: The objective of this study was to determine the epidemiology of Mycoplasma pneumoniae infections at our hospital and to evaluate the prescription of macrolides to empirically treat respiratory infections in children. PATIENTS AND METHODS: A one year prospective study was performed. To find out the prevalence of M. pneumoniae infections, we obtained blood samples of 519 children attending our hospital out-patient department to determine M. pneumoniae IgG levels. In order to establish the incidence, IgM antibodies against M. pneumoniae were measured in 255 children admitted to the hospital showing clinical pictures compatible with this infection. RESULTS: In the first years of life, prevalence of M. pneumoniae infection was low. According to our study, only 3.3% of 1 year-old patients had M. pneumoniae antibodies. Antibody levels increased in children of 5 years or older. The highest rates, between 58.5% and 63.3%, were detected in patients between 8 and 12 years of age. The incidence rate (6.7%) was low among the children admitted. The most frequent clinical entity was pneumonia (82%). The highest rate of infection was found in children of 8 to 10 years. Symtomatology was mainly sub-acute. Crioagglutinins provided the most significant predictive value for etiological diagnosis. CONCLUSIONS: M. pneumoniae infections gain significance in patients over 5 years of age. In our environment, incidence of acute symptomatic infection is low. We consider that both age and presentation of acute respiratory processes should be taken into account when establishing empirical macrolide treatment in children.

[Use of the thermometer among mothers of young children]. / Uso del termómetro entre madres de niños jóvenes.

Due to the importance of fever and its correct measurement, we try to describe in our study the use of the thermometer by a sample of mothers of young children chosen at random in a low-middle class neighborhood. We surveyed them at home and checked their use of the thermometer. We found a frequent and correct usage of the thermometer. We identify the mother's educational level as one indicator of some of the mistakes in their use of the thermometer. We propose specific points to teach every mother when she goes to the pediatrician in order to provide adequate use of the thermometer in children with fever.