A rapid calprotectin test for the diagnosis of pleural effusion.

In previous studies, measuring the levels of calprotectin in patients with pleural effusion (PE) was an exceptionally accurate way to predict malignancy. Here, we evaluated a rapid method for the measurement of calprotectin levels as a useful parameter in the diagnosis of malignant pleural effusion (MPE) in order to minimise invasive diagnostic tests. Calprotectin levels were measured with Quantum Blue® sCAL (QB®sCAL) and compared with the gold standard reference ELISA method. Calprotectin levels in patients with benign pleural effusion (BPE) were significantly higher (p < 0.0001) than for MPE patients. We measured the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and positive and negative likelihood ratios (LRs) for a cut-off value of ≤ 14,150 ng/mL; the diagnostic accuracy was 64%. The odds ratio for PE calprotectin levels was 10.938 (95% CI [4.133 - 28.947]). The diagnostic performance of calprotectin concentration was better for predicting MPE compared to other individual parameters. Comparison of two assays showed a slope of 1.084, an intercept of 329.7, and a Pearson correlation coefficient of 0.798. The Bland-Altman test showed a positive bias for the QB®sCAL method compared to ELISA fCAL®. Clinical concordance between both these methods was 88.5% with a Cohen kappa index of 0.76 (95% CI [0.68 - 0.84]). We concluded that QB®sCAL is a fast, reliable, and non-invasive diagnostic tool for diagnosing MPE and represents an alternative to ELISA that could be implemented in medical emergencies.

Validation of Calprotectin As a Novel Biomarker For The Diagnosis of Pleural Effusion: a Multicentre Trial.

Discriminating between malignant pleural effusion (MPE) and benign pleural effusion (BPE) remains difficult. Thus, novel and efficient biomarkers are required for the diagnosis of pleural effusion (PE). The aim of this study was to validate calprotectin as a diagnostic biomarker of PE in clinical settings. A total of 425 patients were recruited, and the pleural fluid samples collected had BPE in 223 cases (53.7%) or MPE in 137 patients (33%). The samples were all analysed following the same previously validated clinical laboratory protocols and methodology. Calprotectin levels ranged from 772.48 to 3,163.8 ng/mL (median: 1,939 ng/mL) in MPE, and 3,216-24,000 ng/mL in BPE (median: 9,209 ng/mL; p < 0.01), with an area under the curve of 0.848 [95% CI: 0.810-0.886]. For a cut-off value of ≤ 6,233.2 ng/mL, we found 96% sensitivity and 60% specificity, with a negative and positive predictive value, and negative and positive likelihood ratios of 96%, 57%, 0.06, and 2.4, respectively. Multivariate analysis showed that low calprotectin levels was a better discriminator of PE than any other variable [OR 28.76 (p < 0.0001)]. Our results confirm that calprotectin is a new and useful diagnostic biomarker in patients with PE of uncertain aetiology which has potential applications in clinical practice because it may be a good complement to cytological methods.

Significación clínica de la macroprolactina / Clinical significance of macroprolactin

Introducción: La macroprolactina (maPRL) es una variedad molecular de prolactina (PRL) de alto peso molecular y de actividad biológica cuestionable. El objetivo del presente estudio fue valorar la repercusión clínico-analítica de la presencia de maPRL en pacientes con hiperprolactinemia. Pacientes y método: Seleccionamos las muestras con concentraciones de PRL > 50 ng/ml (1.060 MU/l), tras la realización de la técnica de precipitación con polietilenglicol (PEG) 6000, consideramos que presentaban maPRL aquellas con valores de recuperación 50 ng/ml estudiados en un periodo de 24 meses, 22 presentaron maPRL (9,6%), todas mujeres con edad media de 32 años (12-48). El rango de PRL basal fue de 50,5 a 158 ng/ml. El motivo más frecuente de petición de PRL fueron las alteraciones menstruales (el 45% de los pacientes). Para valorar la repercusión clínica, evaluamos la PRL monomérica en estas pacientes y encontramos que en el 36,4% la maPRL se asociaba a aumento de PRL monomérica (grupo A) y en este grupo presentaba clínica hipogonadal el 87,5%. La maPRL se asociaba con concentraciones fisiológicas de PRL monomérica en el 63,6% (grupo B) y en este grupo presentaba clínica de amenorrea sólo 1 (7,14%) paciente, p < 0,05. De las 6 pacientes a las que se realizó estudio radiológico, 2 presentaron adenomas. Se trató con agonistas dopaminérgicos a 6 pacientes y en todas se normalizaron la clínica y los valores de hiperprolactinemia. Conclusiones: En nuestra serie, la presencia de maPRL sólo se acompañó de clínica de disfunción gonadal cuando se asoció a hiperprolactinemia monomérica. La maPRL aislada carece de significado clínico, pero es importante determinarla para evitar un manejo clínico innecesario

Introduction: Macroprolactin (maPRL) is a high molecular weight variant of prolactin (PRL) with reduced bioactivity. The purpose of the present study was to determine the clinical-laboratory repercussions of the presence of maPRL in patients with hyperprolactinemia. Patients and Method: A polyethylene glycol (PEG) precipitation test was used to detect the presence of maPRL in all consecutive samples with a prolactin concentration of > 50 ng/ml (1.060 MU/l). A recovery 50 ng/ml. All the patients with maPRL were women; the mean age was 32 years (12-48). Serum PRL levels ranged from 50.5-158 ng/ml. The most frequent reason for the initial PRL request was menstrual disturbance (45% patients). To study clinical repercussions, monomeric PRL was determined. The results showed that maPRL was associated with an increase of monomeric PRL levels in 36.4% of the patients (group A) and that 87.5% of patients in this group had hypogonadal symptoms. MaPRL was associated with physiological concentrations of monomeric PRL in 63.6% (group B) and only one patient in this group had amenorrhea (7.14%), p < 0.05. Of 6 patients who underwent neuroimaging, pituitary adenomas were identified in 2. Six patients were treated with dopamine agonists. In all 6 of these patients, symptoms and hyperprolactinemic values were resolved. Conclusions: Our results indicate that patients with maPRL only presented symptomatology suggestive of hyperprolactinemia when the monomeric PRL concentration was elevated. MaPRL has limited clinical repercussions but its determination in routine practice is important to avoid inappropriate management