Aviso de valores de alerta por parte del laboratorio clínico en una red de salud universitaria / Laboratory alert value reporting by the clinical laboratory at an academic medical network

Background: An alert value is a result suggesting that the patient is at imminent danger unless appropriate remedial actions begin promptly. Report of alert values (AV) by the clinical laboratories has taken special relevance in recent years due to its contribution to patient's care. Aim: To report results of AV informed during 2007 within the Health Network of the Pontificia Universidad Católica de Chile. Material and methods: Analysis of AV recorded in a centralized database of the laboratories of the health network, between January and December, 2007. Results: Total number of AV was 5.366, which represented 0.3 percent of total examinations and corresponded mainly to the clinical chemistry area. Potassium levels generated the higher number of AV detected, followed by positive blood cultures. Eighty two percent of AV corresponded to hospitalized patients. The greater number of AV was reported to intermediate and intensive care services. Thirty two percent of AV was informed to the physician or professional in charge of the patient within 5 minutes of obtaining the results and 79 percent within 30 minutes. Conclusions: To obtain a real impact on patient management, it is fundamental to shorten the ¡apse between the obtainment of tests results and the warning, supported on appropriate computerized systems, and to spread the procedure to all personnel involved in patient's care (RevMéd Chile 2009; 137: 1137-44).

Presencia de macroprolactina en sueros con normo e hiperprolactinemia: comparación de dos métodos de detección / Comparison of two techniques to detect the presence of macroprolactin in serum

Background: Macroprolactin is biologically inactive but may be detected by immnoassays. This leads to errors in diagnosis and inadequate treatment of patients with hyperprolactinemia. Aim:To assess two techniques to detect the presence of macroprolactin. Material and Methods: Prolactin was measured by immunoassay in 57 serum samples (from 4 males and 53 females aged33 +/- 13 years), before and after precipitation with polyethyleneglycol (PEG) and separation by ultrafiltration. A significant level of macroprolactin was considered to be present when prolactin detected in the supernatant after PEG precipitation or in the ultrafiltrate was less than 40 percent of the initial concentration of prolactin. Results: Prolactin levels fluctuated from 5 to 411 ng/ml. The percentages of recuperation were independent of the initial prolactin concentration. In 12 and 14 percent of samples, using polyethyleneglycol and ultrafiltration respectively, there was a prolactin recuperation of less than 40 percent. Eight and 11 percent of samples with a prolactin concentration of more than 30 ng/ml, had a recuperation of less than 40 percent using polyethyleneglycol and ultrafiltration respectively. Conclusions: Approximately 10 percent of samples with a prolactin concentration over 30ng/ml have recuperation values suggestive of the presence of macroprolactin. There is a good concordance between precipitation using polyethyleneglycol or ultrafiltration.

Pesquisa de sífilis congénita al momento del parto: ¿Suero materno o sangre de cordón? / Diagnosis of congenital syphilis at delivery: Maternal serum or cord blood?

La sífilis congénita (SC) es un problema importante en Chile, con una tasa de 0,25/1.000 recién nacidos (RNs) vivos en el año 2004. En el año 2000, el Ministerio de Salud recomendaba como tamizaje al momento del parto una muestra de sangre de cordón. El Centro de Control y Prevención de Enfermedades, (CDC), Atlanta, E.U.A. recomendó, desde 1998, el tamizaje al parto con suero materno ya que respecto del suero del RN, la sangre de cordón y el suero materno tienen respectivamente hasta 5 y 0,5 por ciento> de falsos negativos. Objetivo: Determinar el mejor tamizaje al momento del parto. Métodos: Se estudiaron muestras de suero materno y sangre de cordón de los RNs durante un año. Se realizó RPR y de ser positiva, pruebas treponémicas confirmatorias (imunocromatográfico Determine®, ELISA Captia® IgG e IgM y microhemaglutinación). Todos los pacientes confirmados fueron vistos por el especialista para definir los casos de SC. Resultados: Entre junio de 1999 y agosto del 2000 se estudiaron 2.741 binomios madre-RN; de éstos 37/2.704 (1,3 por ciento) fueron RPR reactivos. Once eran RPR reactivo en la madre y en el RN (Grupo I), 9 eran RPR reactivo en el RN y no reactivo en la madre (Grupo II) y 17 eran RN con RPR no reactivo y reactivo en la madre (Grupo III). En el Grupo I hubo 64 por ciento> (7/11) de verdaderos (+)s y 36 por ciento (4/11) de falsos (+)s del RPR. En el Grupo II, 9/ 9 (100 por cientoo), correspondieron a falsos (+)s del RPR en sangre de cordón y en el Grupo III, 11/17 (67 por ciento>) correspondieron a falsos (+)s del RPR en sangre materna pero hubo 6/17 (35 por ciento>) que correspondían a sífilis durante el embarazo y en tres de ellas no hubo tratamiento intra-embarazo, por lo que fueron catalogadas como SC y los RNs debieron ser tratados. En total hubo 9 RNs que correspondieron a SC (6 del grupo I y 3 del grupo III). Si sólo se hubiese realizado tamizaje en sangre de cordón, 3 RNs con SC no se hubiesen....

Congenital syphilis (CS) is an important health problem in Chile, with a rate of 0.25/1,000 live newborn (NB) during year 2004. In 2000, the Chilean Ministry of Public Health recommended to perform a screening in cord blood at the moment of delivery. Instead, the Centers for Disease Control and Prevention guidelines recommend the screening in maternal serum since cord blood has up to 5 percent of false (-) versus 0.5 percent of maternal serum, both with respect to the NB serum. Objective: Maternal serum and NB cord blood were studied during one year to determine the best screening method at delivery. Methods: RPR was performed and positive results were confirmed by treponemic test (immunochromatographyDetermine®, ELISA Captia®, Ig and IgM, and MHA-Tp). Serologically confirmed patients were evaluated by the specialist to define CS cases. Results: Between June 1999 and August 2000 2,741 binomies were studied; of these, 37 (1.3 percent) were RPR reactive and 2.704 were non-reactive. In 11 of the 37 reactive cases, mother and NB were RPR reactive (Group I), in 9 cases the NB was RPR reactive and the mother was non-reactive (Group II), and the other 17 were NB non-reactive and mother reactive (Group III). In group I, 7/11 (64 percent) were true (+)s and 4/11(36 percent)) false (+)s of RPR. In group II, 9/9 (100 percent) corresponded to false (+)s of RPR in cord blood, and in group III, 11/17 (65 percent) corresponded to false (+)s of RPR in maternal blood but 6/17 (35 percent) were found to be cases of syphilis during pregnancy. Three of them were not treated opportunely and were designed as CS. In total 9 NB corresponded to CS (6 in group I and 3 in group III). If the screening had been performed only in cord blood, three NB with CS would have not been diagnosed. Conclusion: Even when maternal serum has a high rate of false (+)s, it has better sensitivity than cord blood for the diagnosis of CS, thus it is suggested to perform the screening ...

Evaluación de métodos diagnósticos para sífilis congénita / Evaluation of diagnostic methods for congenital syphilis

La sífilis congénita es un problema relevante en nuestro país. Actualmente no existen exámenes de uso rutinario que permitan confirmar su diagnóstico. En este estudio prospectivo multicéntrico se evaluaron 60 binomios madre-RN que presentaban test no treponémicos (TNT) reactivos. En todas las muestras se realizaron 2 TNT (VDRL y RPR) y 7 test treponémicos (TT): dos evaluaban IgM, uno IgG y cuatro IgM + IgG. La concordancia entre los tests que evaluaban IgG o IgG + IgM fue de 90 por ciento y entre los que evaluaban IgM fue de 87,5 por ciento. Un resultado IgG positivo se observó en 100 por ciento de los binomios cuyas madres presentaron sífilis durante el embarazo o portaban serología residual. La IgM fue positiva en 64 por ciento de las madres con sífilis adecuadamente tratada durante el embarazo, siendo sus neonatos todos IgM negativa. Aquellas madres con un tratamiento inadecuado tuvieron IgM positiva en 82.3 por ciento y sus RN tuvieron IgM positivas en 11,8 por ciento. En conclusión, la IgM materna no aporta al diagnóstico de sífilis congénita, pues su positividad no se correlaciona con el riesgo de que el RN presente este cuadro. La Igm en el RN es útil para el diagnóstico precoz de sífilis congénita, pero su ausencia no descarta esta patología