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Blood Concentration
Reference ranges (reference intervals) for blood tests are sets of values used by a health professional to interpret a set of medical test results from blood samples. Reference ranges for blood tests are studied within the field of clinical chemistry (also known as "clinical biochemistry", "chemical pathology" or "pure blood chemistry"), the area of pathology that is generally concerned with analysis of bodily fluids. Blood test results should always be interpreted using the reference range provided by the laboratory that performed the test. Interpretation A reference range is usually defined as the set of values 95 percent of the normal population falls within (that is, 95% prediction interval). It is determined by collecting data from vast numbers of laboratory tests. Plasma or whole blood In this article, all values (except the ones listed below) denote blood plasma concentration, which is approximately 60–100% larger than the actual blood concentration if the amount ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reference Range
In medicine and health-related fields, a reference range or reference interval is the range or the interval of values that is deemed normal for a physiological measurement in healthy persons (for example, the amount of creatinine in the blood, or the partial pressure of oxygen). It is a basis for comparison for a physician or other health professional to interpret a set of test results for a particular patient. Some important reference ranges in medicine are reference ranges for blood tests and reference ranges for urine tests. The standard definition of a reference range (usually referred to if not otherwise specified) originates in what is most prevalent in a reference group taken from the general (i.e. total) population. This is the general reference range. However, there are also ''optimal health ranges'' (ranges that appear to have the optimal health impact) and ranges for particular conditions or statuses (such as pregnancy reference ranges for hormone levels). Values withi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme Activity
Enzyme assays are laboratory methods for measuring enzymatic activity. They are vital for the study of enzyme kinetics and enzyme inhibition. Enzyme units The quantity or concentration of an enzyme can be expressed in molar amounts, as with any other chemical, or in terms of activity in enzyme units. Enzyme activity Enzyme activity is a measure of the quantity of active enzyme present and is thus dependent on various physical conditions, ''which should be specified''. It is calculated using the following formula: :\operatorname=\operatorname=\operatorname\times\operatorname where :\operatorname= Enzyme activity :\operatorname= Moles of substrate converted per unit time :\operatorname= Rate of the reaction :\operatorname= Reaction volume The SI unit is the katal, 1 katal = 1 mol s−1 (mole per second), but this is an excessively large unit. A more practical and commonly used value is enzyme unit (U) = 1 μmol min−1 (micromole per minute). 1 U corresponds to 16.67 nano ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blood Gas
A blood gas test or blood gas analysis tests blood to measure blood gas tension values, it also measures blood pH, and the level and base excess of bicarbonate. The source of the blood is reflected in the name of each test; arterial blood gases come from arteries, venous blood gases come from veins and capillary blood gases come from capillaries.Seifter JL. Acid-base disorders. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 119 The blood gas tension levels of partial pressures can be used as indicators of ventilation, respiration and oxygenation. Analysis of paired arterial and venous specimens can give insights into the aetiology of acidosis in the newborn. Values measured Blood samples for testing are taken from arterial blood by a radial artery puncture, and from venous blood by venipuncture. Samples of capillary blood are taken using a lancet and capillary action. Samples from capillaries from either the earlobe or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Venipuncture
In medicine, venipuncture or venepuncture is the process of obtaining intravenous access for the purpose of venous blood sampling (also called ''phlebotomy'') or intravenous therapy. In healthcare, this procedure is performed by medical laboratory scientists, medical practitioners, some EMTs, paramedics, phlebotomists, dialysis technicians, and other nursing staff. In veterinary medicine, the procedure is performed by veterinarians and veterinary technicians. It is essential to follow a standard procedure for the collection of blood specimens to get accurate laboratory results. Any error in collecting the blood or filling the test tubes may lead to erroneous laboratory results. Venipuncture is one of the most routinely performed invasive procedures and is carried out for any of five reasons: # to obtain blood for diagnostic purposes; # to monitor levels of blood components; # to administer therapeutic treatments including medications, nutrition, or chemotherapy; # to remov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vein
Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart. In contrast to veins, arteries carry blood away from the heart. Veins are less muscular than arteries and are often closer to the skin. There are valves (called ''pocket valves'') in most veins to prevent backflow. Structure Veins are present throughout the body as tubes that carry blood back to the heart. Veins are classified in a number of ways, including superficial vs. deep, pulmonary vs. systemic, and large vs. small. * Superficial veins are those closer to the surface of the body, and have no corresponding arteries. *Deep veins are deeper in the body and have corresponding arteries. *Perforator veins drain from the superficial to the deep veins. These are usually referred to in the lower limbs and feet. *Communic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thyroid's Secretory Capacity
Thyroid's secretory capacity (''GT'', also referred to as thyroid's incretory capacity, maximum thyroid hormone output, T4 output or, if calculated from serum levels of thyrotropin and thyroxine, as SPINA-GT) is the maximum stimulated amount of thyroxine that the thyroid can produce in a given time-unit (e.g. one second). How to determine GT Experimentally, ''GT'' can be determined by stimulating the thyroid with a high thyrotropin concentration (e.g. by means of rhTSH, i.e. recombinant human thyrotropin) and measuring its output in terms of T4 production, or by measuring the serum concentration of protein-bound iodine-131 after administration of radioiodine. These approaches are, however, costly and accompanied by significant exposure to radiation. ''In vivo'', ''GT'' can also be estimated from equilibrium levels of TSH and T4 or free T4. In this case it is calculated with \hat G_T = or \hat G_T = \hat G_T : Theoretical (apparent) secretory capacity (SPINA-GT) \alpha _ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homeostatic Model Assessment
The homeostatic model assessment (HOMA) is a method used to quantify insulin resistance and beta-cell function. It was first described under the name HOMA by Matthews ''et al.'' in 1985. Derivation The HOMA authors used data from physiological studies to develop mathematical equations describing glucose regulation as a feedback loop. They published computer software that solves the equations, so that insulin resistance and β-cell function can be estimated from fasting glucose and insulin levels. They also published an equation (see below) that gave approximately the same answers as an early version of the computer software. The computer model has since been improved to a HOMA2 model to better reflect human physiology and recalibrated to modern insulin assays. In this updated version it is possible to determine insulin sensitivity and β-cell function from paired fasting plasma glucose and radioimmunoassay insulin, specific insulin, or C-peptide concentrations. The authors recom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Cell
Beta cells (β-cells) are a type of cell found in pancreatic islets that synthesize and secrete insulin and amylin. Beta cells make up 50–70% of the cells in human islets. In patients with Type 1 diabetes, beta-cell mass and function are diminished, leading to insufficient insulin secretion and hyperglycemia. Function The primary function of a beta cell is to produce and release insulin and amylin. Both are hormones which reduce blood glucose levels by different mechanisms. Beta cells can respond quickly to spikes in blood glucose concentrations by secreting some of their stored insulin and amylin while simultaneously producing more. Primary cilia on beta cells regulate their function and energy metabolism. Cilia deletion can lead to islet dysfunction and type 2 diabetes. Insulin synthesis Beta cells are the only site of insulin synthesis in mammals. As glucose stimulates insulin secretion, it simultaneously increases proinsulin biosynthesis, mainly through translational cont ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Percentage
In mathematics, a percentage (from la, per centum, "by a hundred") is a number or ratio expressed as a fraction of 100. It is often denoted using the percent sign, "%", although the abbreviations "pct.", "pct" and sometimes "pc" are also used. A percentage is a dimensionless number (pure number); it has no unit of measurement. Examples For example, 45% (read as "forty-five per cent") is equal to the fraction , the ratio 45:55 (or 45:100 when comparing to the total rather than the other portion), or 0.45. Percentages are often used to express a proportionate part of a total. (Similarly, one can also express a number as a fraction of 1,000, using the term "per mille" or the symbol "".) Example 1 If 50% of the total number of students in the class are male, that means that 50 out of every 100 students are male. If there are 500 students, then 250 of them are male. Example 2 An increase of $0.15 on a price of $2.50 is an increase by a fraction of = 0.06. Expressed as a p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma-glutamyl Transpeptidase
Gamma-glutamyltransferase (also γ-glutamyltransferase, GGT, gamma-GT, gamma-glutamyl transpeptidase; ) is a transferase (a type of enzyme) that catalyzes the transfer of gamma-glutamyl functional groups from molecules such as glutathione to an acceptor that may be an amino acid, a peptide or water (forming glutamate). GGT plays a key role in the gamma-glutamyl cycle, a pathway for the synthesis and degradation of glutathione as well as drug and xenobiotic detoxification. Other lines of evidence indicate that GGT can also exert a pro-oxidant role, with regulatory effects at various levels in cellular signal transduction and cellular pathophysiology. This transferase is found in many tissues, the most notable one being the liver, and has significance in medicine as a diagnostic marker. Nomenclature The name γ-glutamyltransferase is preferred by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology. The Expert Panel on Enzymes of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lactate Dehydrogenase
Lactate dehydrogenase (LDH or LD) is an enzyme found in nearly all living cells. LDH catalyzes the conversion of lactate to pyruvate and back, as it converts NAD+ to NADH and back. A dehydrogenase is an enzyme that transfers a hydride from one molecule to another. LDH exists in four distinct enzyme classes. This article is specifically about the NAD(P)-dependent L-lactate dehydrogenase. Other LDHs act on D-lactate and/or are dependent on cytochrome c: D-lactate dehydrogenase (cytochrome) and L-lactate dehydrogenase (cytochrome). LDH is expressed extensively in body tissues, such as blood cells and heart muscle. Because it is released during tissue damage, it is a marker of common injuries and disease such as heart failure. Reaction Lactate dehydrogenase catalyzes the interconversion of pyruvate and lactate with concomitant interconversion of NADH and NAD+. It converts pyruvate, the final product of glycolysis, to lactate when oxygen is absent or in short supp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alanine Transaminase
Alanine transaminase (ALT) is a transaminase enzyme (). It is also called alanine aminotransferase (ALT or ALAT) and was formerly called serum glutamate-pyruvate transaminase or serum glutamic-pyruvic transaminase (SGPT) and was first characterized in the mid-1950s by Arthur Karmen and colleagues. ALT is found in plasma and in various body tissues but is most common in the liver. It catalyzes the two parts of the alanine cycle. Serum ALT level, serum AST (aspartate transaminase) level, and their ratio (AST/ALT ratio) are commonly measured clinically as biomarkers for liver health. The tests are part of blood panels. The half-life of ALT in the circulation approximates 47 hours. Aminotransferase is cleared by sinusoidal cells in the liver. Function ALT catalyzes the transfer of an amino group from L-alanine to α-ketoglutarate, the products of this reversible transamination reaction being pyruvate and L-glutamate. : L-alanine + α-ketoglutarate ⇌ pyruvate + L-glutama ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
