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Clinical Applications of Immunoassays
Published in Richard O’Kennedy, Caroline Murphy, Immunoassays, 2017
Other bodily fluids like urine, cerebrospinal fluid, amniotic fluid and saliva are also important sample sources for clinical analysis where blood cannot be used (Fig. 6.1). They are less frequently used in immunoassays due to the lack of clinically relevant biomarkers. However, occasionally they are superior to blood. Immunoassays utilising urine can be used for diagnosis of urinary tract diseases by measuring creatinine levels [1], multiple myeloma through Bence Jones proteins [2] or detection of drugs such as amphetamines, opiates and other performance-enhancing drugs [3]. However, the most widely used urine immunoassay is the pregnancy test, which can detect pregnancy within two days of fertilisation based on the detection of human choriogonadotropin (hCG) [4]. Cerebrospinal fluid (CSF), which is more difficult to access and requires a lumbar puncture procedure, can be used to detect the presence of lactate or proteins such as alpha cryptococcal antigen, to test for meningitis, or more recently for cryptococcosis [5]. Amniotic fluid, which surrounds the foetus in the womb throughout the pregnancy, can be used for the analysis of congenital abnormalities. A sample of the amniotic fluid can be taken from the amniotic sac with a needle in a procedure called amniocentesis. Clinical immunoassays utilising amniotic fluid are applied for instance for analysis of alpha-fetoprotein (AFP) which indicates neural tube or abdominal wall defects and chromosomal conditions of the foetus [6]. Saliva is the most easily accessible bodily fluid and it can be used to measure cortisol concentrations for the diagnosis of hypercortisolism and adrenal insufficiency [7]. Since cortisol can directly diffuse into saliva, salivary cortisol immunoassays are more accurate than measuring free cortisol in serum.
Effect of umbilical cord length on early fetal biomechanics
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2021
Juan Felipe Sánchez Gutiérrez, Mercedes Olaya-C, Jorge Andrés Franco, Johana Guevara, Diego Alexander Garzón-Alvarado, María Lucía Gutiérrez Gómez
Even earlier, in gestation, another important structure, the amniotic sac, appears at the beginning of the second week from a layer of cells expanding into a thin membrane, the amnion. This structure is completely established by eight weeks of gestation (Schoenwolf et al. 2014). Moreover, fluid known as the amniotic fluid (AF) begins to collect within the sac (Schoenwolf et al. 2014). This fluid functions to facilitate molecule transport between the mother and the developing embryo/fetus (Underwood et al. 2005). Additionally, the AF is a protective liquid that serves as a mechanical buffer, allowing fetal movement and growth. The AF and the UC are important structures that participate in the correct embryo and fetal development and movement.