Biochemistry

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.

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.

High Performance Liquid Chromatography-Mass Spectrometry

Recently, and in collaboration with the Hospital Pharmacy Service of the Hospital

Mutua Terrassa University, a high-efficiency chromatography analytical system in tandem with a mass spectrometry detector (HPLC-MS) has been incorporated into Catlab.

This combination of analytical techniques will allow our laboratory to have,the considered, gold-standard method in clinical laboratory, and thus have the ability to measure analytes with great sensitivity and specificity. The study of immunosuppressants will be the first to make use of this technique and new ones will be added later.

Results obtained in Catlab using the new "Prenatal screening protocol for congenital anomalies in Catalonia"

In year 2018 and later in 2021, the screening protocol for congenital anomalies was updated. The latest updates to the protocol include the determination of Cell-free fetal DNA in patients at intermediate and high risk. These new protocols have made it possible to extend the non-invasive study to intermediate-risk patients and to avoid invasive tests in high-risk patients in which Cell-free fetal DNA tested negative.

In Catlab between March and December 2021, 3038 first trimester screenings were performed. Applying the aforementioned protocols, the improvement in the detection of anomalies was shown as 2 alterations were detected in patients with intermediate risk using fetal DNA, as well as the decrease in the need for invasive tests by avoiding this intervention in 66 high-risk patients.

Anti-Müllerian hormone(AMH)- Aplications and quantification.

AMH is a glycoprotein belonging to the transforming growth beta factor superfamily. It has recently emerged as an early and accurate biomarker for ovarian reserve and ovarian aging assesssment. Thus, the determination of this hormone has various applications such as the diagnosis and follow-up of patients with polycystic ovary syndrome or ovarian granulosa cell tumors, among others. In men, its determination is also used for the study of hypogonadism or early puberty.

At Catlab during the year 2020, AMH test has been internalized, using Lumipulse Analyzer,by Fujirebio INC.

The determination is performed using a two-step chemiluminescent immunoassay method that will eventually generate a luminic signal proportional to the amount of AMH present in the sample.

BIOCHEMISTRY - Possible interference by Biotin in some Laboratory tests

Biotin is a water-soluble vitamin that participates in cell proliferation, embryonic development, and in immunological and metabolic functions. It is commonly found in many foods, but also in some vitamin supplements. In 2017, the FDA warned about possible interference in some laboratory tests, due to the high presence of biotin. Catlab, following international recommendations, has been substituting some reagents to avoid possible interference with biotin.

BIOCHEMISTRY - Fecal occult blood updates

Colorectal cancer ranks second in cancer incidence and mortality in developed countries. Recently in Catlab a series of changes have been made to update the technique and improve clinical interpretation. The analyzer and the collection container have been changed. The unit of the expressed results, and the cut-off point has been changed too.

BIOCHEMISTRY - Vitamin D: Update

Recently, the reference values that appear in our report laboratory of Vitamin D have been modified. Currently, there are different methods for measuring them, and the reference values depend on the population studied. They vary with sex, age, seasonal period, geographical latitude, diet, body mass index, ethnic group ... With this great variability, we have decided to update the reference values following the recommendations of the "Protocol d'indicacions per la mesura de vitamina D" approved by the ICS.

TUMOR MARKERS - New markers in prostate cancer.

Prostate cancer continues to be the most common in men, and PSA is the most commonly used marker. The low specificity of PSA in detecting cancer causes a large number of negative biopsies, and also does not help that it can not differentiate between lethal and non-lethal cancer. That is why, in recent multicenter studies, ProPSA (free PSA isoform) and phi index are being positioned as more specific markers.

BIOCHEMISTRY - Biomarkers for infection / sepsis.

The overall mortality in patients with sepsis is between 10-20%, between 20-50% in those with severe sepsis and between 40-80% in patients with septic shock. The immediate adoption of diagnostic-therapeutic decisions will directly affect the evolution, prognosis and survival, therefore, the availability of early and accurate biomarkers is key to effective clinical management of infections.