فصلنامه آزمایشگاه و تشخیص
پیاپی 48 (تابستان 1399)

In response to the outbreak of COVID-19, caused by the SARS-CoV-2 virus, several tests are needed for diagnosis of acute illness, contact tracking, diagnosis of asymptomatic infections, and assessment of herd immunity. While PCR is the standard test in acute type, serological tests have been developed and used to meet diagnostic needs due to the widespread prevalence of the disease.
Unlike the availability of high-throughput PCR assays, cross-reactivity is a major challenge for COVID-19 antibody test. Given that there are six other coronaviruses that infect humans, the development of highly specific serological methods to identify infected patients will be of paramount importance.
Laboratory diagnostic tests play an important role in preventing the spread of infectious diseases, as evident in the case of COVID-19. Within incipient days of the release of the SARS-CoV-2 genome, PCR tests were rapidly being pioneered to diagnose patients with acute pneumonia in China and worldwide. As the disease spread, it became clear that PCR testing alone could not meet the needs of the society and shortcomings gradually appeared, such as lack of ability in retrospective contact tracing, lack of ability in detecting asymptomatic patients, and inability in assessing herd immunity.
Although in several countries, serological tests are being used in contact tracking, seroepidemiological studies and planning and determining different strategies in controlling COVID-19, unfortunately, different opinions about the use and quality of serological tests are given in cyberspace which are mainly based on little information at the beginning of the production of serology kits and at the time of low prevalence of the disease.
This paper is an overview of the use of different strategies to increase the sensitivity, specificity and positive predictive value of serological tests and examining the impact of various factors on these characteristics.
Scientists have developed a large number of antibody assays, and many of these tests are now commercially available. Although none of these measurements have been fully validated, FDA has issued Emergency Use Authorization (EUA) for some tests while emphasizing the need for further validation. This is because the widespread use of unapproved tests could lead to policies that exacerbate rather than control the current SARS-CoV-2 epidemic.

Candida microorganisms frequently exist as saprophytes on the external genitalia or urethra, however, yeast in measurable quantities are found in <1% of clean voided urine specimens. The overall frequency of Candida infections in hospitals has increased by 200% to 300% in the last decade, such that in a general hospital 5% of urine cultures may yield Candida species, and in tertiary-care centers Candida species account for approximately 10% of all urinary isolates. Most positive cultures are isolated or transient findings of little significance and represent colonization rather than true infection, and less than 10% of candidemias are the consequence of candiduria, nevertheless, Candida urinary tract infections have emerged as important nosocomial infections.
The most common pathogenic mechanism of urinary tract infections by Candida spp. Is UTI hematogenous spread (secondary candidiasis of the urinary tract). Primary candidiasis of the urinary tract is almost exclusively nosocomial and occurs mainly in the presence of an indwelling urinary catheter. Urinary obstruction, diabetes mellitus, or prior urinary tract procedures. Occasionally, primary UTI by Candida spp. Can lead to disseminated infection.
The spectrum of candidiasis in the urinary tract ranges from benign colonization with no clinical significance (very common) to urethritis (usually associated with balanitis), asymptomatic cystitis, pyelitis, fungus ball of the ureter, papillary necrosis, or perinephric or renal abscesses.

Detection, identification and measurement of microbial pathogens is critical for protecting public health. Although microbial culture-based tests and molecular techniques are currently the most commonly used, these techniques are time-consuming and require complex tools and experienced individuals. Consequently, it is costly to analyze these techniques. The emergence of the aptamer led to the elimination of defects of other molecular methods. Also, the ability to specifically bind aptamers to different targets has provided them with great potential that can be used to identify various pathogens.  Aptamers are separated from synthetic libraries by a gradual laboratory process called SELEX. The SELEX steps include duplication of library construction, docking / duplication and replication. This study is a review of the use of aptamers as a diagnostic and therapeutic agent for pathogenic bacteria. Aptamers have wide-ranging applications due to their high stability as well as their high affinity for clinical applications in the treatment and diagnosis of pathogenic bacteria. The capabilities and applications of aptamers and their Sensors made in various fields of science, especially the detection and identification of viruses, toxins and pathogenic bacteria, make it increasingly important to research and study this field.

Many of the conflicts occurring in the Medical Labs could be directly linked to the presence of multiple generations. There have been three generations in the workplace at any given time. We are at a unique time where there are four generations all coexisting in the labs. The article describes generalized behaviors of each generation and the correlation of these unique trails on medical lab proffessionalists.

Klotho is an anti-aging single-pass membrane protein that is mainly produced in the kidney. The level of soluble klotho decreases with age and the klotho gene is associated with an increased risk of age-related diseases, such as diabetes, skin atrophy, chronic kidney disease, ataxia and cancer.
The klotho gene is composed of five exons and encodes a membrane glycoprotein located in the plasma membrane.
The 3 forms of klotho protein have a specific function:1-klotho forms a complex membrane protein with fibroblast growth factor receptors (FGFR) and acts as a binding cofactor for FGF23, which is involved in the regulation of aging and the development of chronic diseases through the regulation of ionized phosphorus and vitamin D metabolism.
2- Secretory klotho as a humoral agent has pleiotropic activity which includes regulation of oxidative stress, growth factor signaling and ion homeostasis. Secretory klotho also plays a role in organ protection.
3- The intracellular form of Klotho suppresses inflammation caused by cellular aging and mineral metabolism.

Background and Goals:

Helicobacter pylori is a gram-negative micro-aerophilic bacillus, with a global prevalence. The bacterium causes a wide range of gastrointestinal diseases, including chronic gastritis, peptic ulcer, gastric cancer and MALT. Due to the importance of this bacterium in causing gastrointestinal disorders, this study was conducted to evaluate the serum levels of antibodies against Helicobacter pylori in clients of Islamshahr Health Center by ELISA.

In this cross-sectional study, the serum of 650 patients referred to Islamshahr Health Center who had clinical symptoms was collected. The IgG, IgA and IgM antibodies to Helicobacter pylori were then measured using the ELISA method.

From all the samples performed (650 samples), the results were as follows: 47.08% (306) IgG, 14.62% (95) IgA, 4.62% (30) IgM. The highest IgG antibody frequency was observed in the age group of 46-60 years (65%). No significant association (P = 0.6) was observed between the mean titers of IgA, IgM and IgG antibodies with age.

Due to the high percentage of positive titers of IgG and IgA antibodies against Helicobacter pylori, it is necessary to use codified educational and health programs to reduce the prevalence of this bacterium.