serum potassium

Potassium in the human body is mainly derived from food. More than 90% of the potassium in the food is absorbed in the intestines in a short period of time, and 90% of the potassium absorbed into the blood is excreted from the kidney within 4 hours. Most of the potassium ions (98%) are present in the cells, and a small amount is present in the extracellular fluid at a constant concentration. The tissue cells contained an average of K + 150 mmol / L, the red blood cells contained K + about 105 mmol / L, and the serum contained K + about 4 ~ 5 mmol / L. Potassium ions in the body are constantly exchanged between cells and body fluids to maintain homeostasis. Potassium is the main cation that maintains the physiological activities of cells. It plays an important role in maintaining the body's normal osmotic pressure and acid-base balance, participating in sugar and protein metabolism, and ensuring the normal function of nerve muscles. Basic Information Specialist classification: growth and development check classification: biochemical examination Applicable gender: whether men and women apply fasting: fasting Analysis results: Below normal: Causes hypokalemia. Normal value: Serum potassium: 3.5-5.3mmol/L Above normal: Causes high blood potassium. negative: Positive: Tips: Use deionized water for flushing water or dilute water to reduce the interference of potassium ions in the water. Normal value Flame photometer method: 3.5 to 5.3 mmol/L (3.5 to 5.3 mEq/L). Ion selective depolarization method: 3.9 to 5.3 mmol/L (3.9 to 5.3 mEq/L). Enzyme kinetics: 3.5 to 5.1 mmol/L (3.5 to 5.1 mEq/L). Clinical significance 1, hypokalemia (1) Ingestion reduces long-term fasting, anorexia, and low food. (2) Potassium undergoes intracellular insulin therapy, alkalosis, and periodic paralysis (hypokalemia). (3) Increased potassium excretion in the urine: 1 increased secretion of mineralocorticoids, primary aldosteronism, 17α-hydroxylase deficiency, Cushing syndrome, atopic ACTH tumor, Bartter syndrome (low aldosteronism and hypokalemia alkalosis) Glomerular hyperplasia syndrome), secondary aldosteronism (malignant hypertension, renal vascular hypertension), juxtaglomerular cell tumor, a large number of oral licorice and so on. 2 distal renal tubular flow increased diuretic (potassium), potassium loss nephritis. 3 renal tubular acidosis. 4 Fanconi syndrome (Fankoni syndrome). (4) Loss of potassium from the digestive tract increases vomiting, diarrhea, colon cancer, villus adenocarcinoma, Zollinger-Ellison's syndrome (Zhu-Ai syndrome pancreatic ulcer), WDHA syndrome (watery diarrhea and hypokalemia) Symptoms associated with islet cell adenoma syndrome), taking laxatives. (5) A lot of sweating. 2, high blood potassium (1) excessive potassium supplementation (especially when renal insufficiency is reduced) or excessive potassium supplementation. (2) Potassium migrates to the outside of the cell, pseudohyperkalemia, acidosis, insulin deficiency, tissue necrosis, the use of large doses of digitalis, periodic paralysis (hyperkalemia), and the use of succinylcholine. (3) urinary potassium excretion reduces acute and chronic renal failure or decreased extracellular fluid volume. (4) Corticosteroid activity reduces Edison's disease, renin-angiotensin-aldosterone system dysfunction, pseudo aldosterone hypoxia, drugs (spirolactone) and the like. Low results may be diseases: periodic paralysis results may be high. Possible diseases: precautions for hyperkalemia Enzyme kinetics: 1. The experimental parameters introduced in this Law are for reference only, and the actual operation is strictly based on the manual. 2. Use deionized water to rinse water or dilute water to reduce the interference of potassium ions in the water. 3. Each reconstituted reagent must be recalibrated. Inspection process 1. Flame photometer method: At present, the flame photometer used in each laboratory has two measurement methods: direct measurement and internal standard measurement. (1) Direct measurement method: firstly prepare different concentrations of potassium standard solution, measure the intensity of the emitted light and record the reading, then use the concentration as the abscissa, the galvanometer reading as the ordinate, draw a standard curve, and then read according to the specimen. Check potassium and content from the standard curve. The serum potassium concentration is low, the ground state potassium atoms are less in the flame, the atomic absorption is less, and the sample has a linear relationship within 10 mmol/L. The single standard solution can also be used to calculate the measurement result. (2) Internal standard measurement method: The sample is diluted with a standard dilution solution containing lithium, and the ratio of the potassium electric signal to the lithium battery signal is used as a quantitative parameter to perform measurement calculation. Most of the flame photometers can directly display the measurement result. This method can reduce the error caused by flame instability, thereby improving precision and accuracy. 2. Ion selective depolarization method: There are two methods for measuring potassium using an ion selective electrode, one is a direct potential method and the other is an indirect potential method. (1) Direct potential method: The sample (serum, plasma, whole blood) or standard solution directly enters the ISE pipeline for potential analysis without dilution. This method can truly reflect the activity of ions in serum that is physiologically significant, so the reporting method is serum potassium mmol/L activity. (2) Indirect potential method: the sample (serum, plasma, cerebrospinal fluid) and the standard solution should be diluted with a dilution of the specified ionic strength and pH, and then sent to the electrode tube to determine its potential, then the pH of the sample and the standard solution. The value tends to be consistent with the ionic strength, and the ion activity of the measured solution is equal to the ion concentration. Reported in mmol/L concentration. Different models of ISE analyzers operate differently. Generally, the following steps are required: 1 Turn on the instrument and clean the pipe. The electrode is activated with an activating solution. 2 Two-point calibration is performed with a low and high value slope calibrator suitable for the instrument. 3 The sample of the indirect potential method is automatically diluted by the instrument and then measured. The direct potential method can directly measure the sample into the electrode tube. 4 The measurement result is calculated by the computer in the instrument and the data is printed out. 5 After using it every day, clean the electrode and the pipe and then turn it off, or it won't turn off. Not suitable for the crowd A patient with hemophilia and severe clotting factor deficiency. Adverse reactions and risks Discomfort: There may be pain, swelling, tenderness, and visible subcutaneous ecchymosis at the puncture site.