Catlab Reports Bulletin

Alzheimer's disease: CSF and plasma biomarkers

Alzheimer's disease is a progressive neurodegenerative disorder that is the most common cause of dementia worldwide.

Biomarkers in CSF and plasma allow for diagnosis in preclinical and mild clinical stages of the disease, and in the future will be essential for monitoring neurological changes in response to drugs that prevent disease progression.

Contribution of diagnostic syndromic panels to emergency management Pediatric infectious: regarding an outbreak of Mycoplasma pneumoniae.

Atypical pneumonia is a common cause of respiratory infection in the paediatric population with Mycoplasma pneumoniae being one of the main aetiological agents. Rapid and accurate identification of M. pneumoniae is essential to guide antibiotic treatment, especially in the context of epidemic outbreaks, where clinical diagnosis may be non-specific. The introduction of multiplex syndromic panels in the emergency microbiology laboratory allows rapid and simultaneous detection of multiple pathogens. We have shown that this has a significant impact on antimicrobial prescribing in the paediatric population, reducing the unnecessary use of broad-spectrum antibiotics and favouring a targeted therapeutic approach, as the result is available in approximately 2 hours.

Procalcitonin and sepsis in critically ill patients

Sepsis is defined by the Sepsis-3 consensus as life-threatening organ dysfunction caused by a dysregulated host response to infection. Each hour of delay in diagnosis, attributable to failure to recognize it during patient admission, is associated with a 7% reduction in survival.

The need for early diagnosis has led to the search for a specific biomarker, which also allows risk stratification and prognosis and whose variation allows monitoring of subsequent evaluation. Procalcitonin (PCT) has revolutionized the management of sepsis, allowing a more accurate diagnosis and more efficient antibiotic management. This approach, combined with clinical strategies and the role of the laboratory, has significantly improved patient care.

The determination of PCT helps predicting bacterial infection, distinguishing it from viral infections and other inflammatory processes, and to differentiate between localized and systemic bacterial infection. It should not be used in isolation, but in combination with clinical evaluation and other microbiological data to make therapeutic decisions.

Multiple Myeloma: Genetic Study

Multiple myeloma (MM) is a hematologic cancer that affects plasma cells in the bone marrow, and chromosomal alterations are central to its diagnosis and prognosis. Genetic abnormalities include primary changes such as IGH gene rearrangements and secondary changes such as TP53 deletion, which influence survival and response to treatment. Prognosis is calculated using the international staging system (ISS), which is based on factors such as β2-microglobulin and albumin levels. Over time, revisions to the ISS have been developed to improve prognostic accuracy. The R-ISS adds the analysis of high-risk cytogenetic alterations such as t(4; 14), t(14; 16) and del(17p). Recently, the R2-ISS version incorporated the 1q gain alteration as a high-risk factor. These revisions help to tailor therapeutic strategies and improve patient outcomes. A key tool to identify these alterations is the fluorescence in situ hybridization (FISH) technique, which allows the detection of specific chromosomal abnormalities in plasma cells. At Catlab we perform the MultiFISH technique, which facilitates the analysis of the most relevant genetic alterations at once, improving diagnosis and personalization of treatment. In summary, the MultiFISH technique facilitates the detection of specific chromosomal alterations and guides the risk stratification,to provide personalized treatments and improve therapeutic response in patients with multiple myeloma.

How much do you know about cortisol in saliva?

Saliva as an easily obtained alternative sample for cortisol analysis. Its pathophysiology, current applications, analysis methods and advantages and disadvantages of its use in clinical practice.

Whooping cough is on the rise: Epidemiological situation in the Vallès area

Whooping cough, caused by the bacterium Bordetella pertussis, is an endemic disease that has re-emerged in Catalonia and worldwide since the end of 2023. It is characterized by cyclical outbreaks every 3-5 years and can affect people of all ages. Neither natural infection with B. pertussis nor vaccination confers long-lasting immunity, so reinfections are frequent.

Transmission occurs mainly through direct contact and inhalation of droplets from infected people when coughing. In infants under 6 months of age, the disease presents a higher risk of complications (pneumonia, encephalopathy, sepsis) and can cause the death of the patient.

Diagnosis is made by serological tests (indirect) or real-time PCR (direct), the latter being the most specific and currently the main method for diagnosing this disease. Since the end of 2023, more than 16,000 samples have been processed in our Laboratory with a notable increase in cases in children aged 10 to 14 years throughout the epidemic outbreak.

Genetic study of MGMT gene promoter methylation in glioblastoma multiforme.

Glioblastoma multiforme(GBM)is an aggressive type of brain tumor with a poor prognosis. The usual chemotherapy treatment with temozolomide (TMZ) is more effective in patients with a methylated MGMT gene promoter. The MGMT gene encodes an enzyme with a DNA repair function, and the inactivation of this gene through methylation, results in tumors being more sensitive to alkylating agents such as TMZ.

At CATLAB, we have recently incorporated the study of the methylation status of the MGMT gene promoter, using real-time PCR in tissue samples preserved in paraffin, treated with bisulfite. The presence of methylation indicates a greater response to chemotherapy and a better prognosis, while the absence of methylation predicts resistance to therapy.

This test helps to personalize treatment and improve therapeutic decisions for patients with GBM.

Initial evaluation of patients with lymphocytosis

In adults, lymphocytosis is considered to be an absolute lymphocyte count greater than 4x109/L, and in children up to 10 years of age, greater than 7x109/L.

To assess lymphocytosis, it is necessary to take into account patient's age, clinical history, time of onset and evolution of lymphocytosis, physical examination (lymph node areas, liver, spleen), laboratory parameters and morphological findings of lymphocytes.

Causes can be divided into 2 large groups: reactive lymphocytosis and clonal lymphocytosis or lymphoproliferative syndromes.

Below, we will summarize lymphopoiesis, discuss following steps in the initial study of patients and list the main causes,while describing morphological findings found in the review of the smear. In addition, we will explain the Catlab work methodology for the study of this frequent alteration.

Use of preoteinogram: Keys for demand optimization

The proteinogram is the main method for detecting and monitoring monoclonal components (MC) in patients with suspected or affected monoclonal gammopathy (MG). Average age MG diagnosis is 65 years, with an overall incidence of 65 cases/100,000 inhabitants/year in those over 60 years of age, and 5 cases/100,000 inhabitants/year in those under 60 years of age. Due to the marked difference in incidence based on age, Clinical Laboratory Societies indicate that it is not necessary to request this test in patients <50 years of age if there is no clinical suspicion of GM, nor to perform GM screening in the general population, given the lack of data supporting an improvement in patient prognosis. However, in daily clinical practice, we encounter many requests for proteinograms in contexts other than GM screening.

Diagnosis of malabsorption and lactose intolerance. Gaxilose

test.

Lactose is a disaccharide formed by glucose and galactose that is present in milk and its derivatives. For its assimilation, the enzyme lactase is necessary to hydrolyze lactose into its two components, glucose and galactose. With the end of lactation, the expression of this enzyme decreases leading to lactose malabsorption. The association of symptoms with this malabsorption is called lactose intolerance.

Both malabsorption and lactose intolerance are underdiagnosed in our environment because they share symptoms with other pathologies or because in some cases the symptoms may be atypical without a clear relationship with dairy intake. To determine lactose malabsorption, in Catlab we perform the gaxylose urine test, a non-invasive test that is performed in an automated way.