Potassium test Information | Mount Sinai

Hypokalemia test; Hyperkalemia test; K+

This test measures the amount of potassium in the fluid portion (serum) of the blood. Potassium (K+) helps nerves and muscles communicate. It also helps move nutrients into cells and waste products out of cells.

Potassium levels in the body are mainly controlled by the hormone aldosterone.

Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.

How the Test is Performed

A blood sample is needed. Most of the time, blood is drawn from a vein located on the inside of the elbow or the back of the hand.

How to Prepare for the Test

Many medicines can interfere with blood test results.

• Your health care provider will tell you if you need to stop taking any medicines before you have this test.
• DO NOT stop or change your medicines without talking to your provider first.

How the Test will Feel

You may feel slight pain or a sting when the needle is inserted. You may also feel some throbbing at the site after the blood is drawn.

Why the Test is Performed

This test is a regular part of a basic or comprehensive metabolic panel.

You may have this test to diagnose or monitor kidney disease. The most common cause of a high blood potassium level is kidney disease.

Potassium is important to heart function.

• Your provider may order this test if you have signs of high blood pressure or heart problems.
• Small changes in potassium levels can have a big effect on the activity of nerves and muscles, especially the heart.
• Low levels of potassium can lead to an irregular heartbeat or other electrical malfunction of the heart.
• High levels cause decreased heart muscle activity.
• Either situation can lead to life-threatening heart problems.

It may also be done if your provider suspects metabolic acidosis (for example, caused by uncontrolled diabetes) or alkalosis (for example, caused by excess vomiting).

Sometimes, the potassium test may be done in people who are having an attack of paralysis.

Normal Results

The normal range is 3.7 to 5.2 milliequivalents per liter (mEq/L) 3.70 to 5.20 millimoles per liter (millimol/L).

Normal value ranges may vary slightly among different laboratories. Talk to your provider about the meaning of your specific test results.

The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.

What Abnormal Results Mean

High levels of potassium (hyperkalemia) may be due to:

• Addison disease (rare)
• Blood transfusion
• Certain medicines, including angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), and the potassium-sparing diuretics spironolactone, beta adrenergic blockers, amiloride and triamterene
• Crushed tissue injury
• Hyperkalemic periodic paralysis
• Hypoaldosteronism (very rare)
• Kidney insufficiency or failure
• Metabolic or respiratory acidosis
• Red blood cell destruction
• Too much potassium in your diet

Low levels of potassium (hypokalemia) may be due to:

• Acute or chronic diarrhea
• Cushing syndrome (rare)
• Diuretics such as hydrochlorothiazide, furosemide, torsemide, and indapamide
• Hyperaldosteronism
• Hypokalemic periodic paralysis
• Not enough potassium in the diet
• Renal artery stenosis
• Renal tubular acidosis (rare)
• Vomiting

Risks

If it is hard to get the needle into the vein to take the blood sample, injury to the red blood cells may cause potassium to be released. This may cause a falsely high result.

Mount DB. Disorders of potassium balance. In: Yu ASL, Chertow GM, Luyckx VA, Marsden PA, Skorecki K, Taal MW, eds. Brenner and Rector’s The Kidney. 11th ed. Philadelphia, PA: Elsevier; 2020:chap 17.

Patney V, Whaley-Connell A. Hypokalemia and hyperkalemia. In: Lerma EV, Sparks MA, Topf JM, eds. Nephrology Secrets. 4th ed. Philadelphia, PA: Elsevier; 2019:chap 74.

Seifter JL. Potassium disorders. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 109.

Last reviewed on: 5/1/2021

Reviewed by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A. D.A.M. Editorial team.

Low blood potassium: MedlinePlus Medical Encyclopedia

URL of this page: //medlineplus.gov/ency/article/000479.htm

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Low blood potassium level is a condition in which the amount of potassium in the blood is lower than normal. The medical name of this condition is hypokalemia.

Potassium is an electrolyte (mineral). It is needed for cells to function properly. You get potassium through food. The kidneys remove excess potassium through the urinary system to keep a proper balance of the mineral in the body.

Common causes of low blood potassium include:

• Medicines, such as diuretics (water pills), certain antibiotics (amphotericin B, chloroquine at toxic levels)
• Diarrhea or vomiting
• Eating disorders (such as bulimia)
• Hyperaldosteronism
• Laxative overuse, which can cause diarrhea
• Chronic kidney disease
• Low magnesium level
• Sweating
• Genetic disorders, such as hypokalemic periodic paralysis, Bartter syndrome

A small drop in potassium level often does not cause symptoms, which may be mild, and may include:

• Constipation
• Feeling of skipped heart beats or palpitations
• Fatigue
• Muscle damage
• Muscle weakness or spasms
• Tingling or numbness

A large drop in potassium level may lead to abnormal heart rhythms, especially in people with heart disease. This can cause you to feel lightheaded or faint. A very low potassium level can even cause your heart to stop.

Your health care provider will order a blood test to check your potassium level. Normal range is 3.7 to 5.2 mEq/L (3.7 to 5.2 mmol/L).

Other blood tests may be ordered to check levels of:

• Glucose, magnesium, calcium, sodium, phosphorous
• Thyroid hormone
• Aldosterone

An electrocardiogram (ECG) to check the heart may also be done.

If your condition is mild, your provider will likely prescribe oral potassium pills. If your condition is severe, you may need to get potassium through a vein (IV).

If you need diuretics, your provider may:

• Switch you to a form that keeps potassium in the body. This type of diuretic is called potassium-sparing.
• Prescribe extra potassium for you to take every day.

Eating foods rich in potassium can help treat and prevent low level of potassium. These foods include:

• Avocados
• Baked potato
• Bananas
• Bran
• Carrots
• Cooked lean beef
• Milk
• Oranges
• Peanut butter
• Peas and beans
• Salmon
• Seaweed
• Spinach
• Tomatoes
• Wheat germ

Taking potassium supplements can usually correct the problem. In severe cases, without proper treatment, a severe drop in potassium level can lead to serious heart rhythm problems that can be fatal.

In severe cases, life-threatening paralysis may develop, such as with hypokalemic periodic paralysis.

Call your provider right away if you have been vomiting or have had excessive diarrhea, or if you are taking diuretics and have symptoms of hypokalemia.

Potassium – low; Low blood potassium; Hypokalemia

• Blood test

Mount DB. Disorders of potassium balance. In: Yu ASL, Chertow GM, Luyckx VA, Marsden PA, Skorecki K, Taal MW, eds. Brenner and Rector’s The Kidney. 11th ed. Philadelphia, PA: Elsevier; 2020:chap 17.

Seifter JL. Potassium disorders. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 109.

Updated by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

Normal vector of the plane, coordinates of the normal vector of the plane, vector of the normal to the plane

There are a number of tasks that need a normal vector on the plane to solve than the plane itself. Therefore, in this article we will get the answer to the question of determining the normal vector with examples and visual drawings. Let us define vectors of three-dimensional space and plane by equations.

Normal vector of the plane – definition, examples, illustrations

To make the material easy to assimilate, it is necessary to first study the theory of the line in space and its representation on the plane and vectors.

Definition 1

A normal vector of the plane is any non-zero vector that lies on a line perpendicular to the given plane.

It follows that there is a large number of normal vectors in the given plane. Consider the figure below.

Normal vectors are on parallel lines, so they are all collinear. That is, with a normal vector n→ located in the γ plane, the vector t n→, having a non-zero value of the parameter t, is also a normal vector of the γ plane. Any vector can be considered as a directing vector of a straight line that is perpendicular to this plane.

There are cases when the normal vectors of the planes coincide due to the perpendicularity of one of the parallel planes, since the line is also perpendicular to the second plane. It follows that the normal vectors of perpendicular planes must be perpendicular.

Consider the example of a normal vector on a plane.

Rectangular coordinate system Oxyz in 3D space is specified. The coordinate vectors i→, j→, k→ are considered normal vectors of the Oyz, Oxz and Oxy planes. This judgment is correct, since i→, j→, k→ are non-zero and are located on the coordinate lines Ox, Oy and Oz. These lines are perpendicular to the coordinate planes Oyz, Oxz and Oxy.

Coordinates of the normal vector of the plane – finding the coordinates of the normal vector of the plane from the equation of the plane

The article is intended to teach how to find the coordinates of the normal vector of the plane with the known equation of the plane of the rectangular coordinate system Oxyz. To determine the normal vector n→=(A, B, C) in the plane, it is necessary to have a general equation of the plane, which has the form Ax+By+Cz+D=0. That is, it is enough to have the equation of the plane, then it will be possible to find the coordinates of the normal vector.

Example 1

Find the coordinates of the normal vector belonging to the plane 2x-3y+7z-11=0.

Solution

By condition, we have the equation of the plane. It is necessary to pay attention to the coefficients, since they are the coordinates of the normal vector of the given plane. From here we get that n→=(2, -3, 7) is the normal vector of the plane. All plane vectors are given by the formula t n→=2 t, -3 t, 7 t, t is any non-zero real number.

Answer: n→=(2, -3, 7).

Example 2

Determine the coordinates of the direction vectors of the given plane x+2z-7=0.

Solution

By condition, we have that an incomplete equation of the plane is given. To see the coordinates, you need to convert the equation x+2z-7=0 to the form 1 x+0 y+2z-7=0. From here we get that the coordinates of the normal vector of this plane are equal to (1, 0, 2). Then the set of vectors will have the following notation (t, 0, 2 t), t∈R, t≠0.

Answer: (t, 0, 2 t), t∈R, t≠0.

Using the equation of the plane in segments, which has the form xa+yb+zc=1, and the general equation of the plane, it is possible to write the normal vector of this plane, where the coordinates are 1a, 1b, 1c.

Knowledge of the normal vector makes it easy to solve problems. Frequently encountered tasks are tasks with proofs of parallelism or perpendicularity of planes. The solution of problems for compiling equations of a given plane is noticeably simplified. If there is a question about finding the angle between planes or between a straight line and a plane, then the formulas for the normal vector and finding its coordinates will help with this.

Author:
Irina Maltsevskaya

Teacher of mathematics and informatics. Department of Business Informatics, Russian University of Transport

Fomina Clinic – a network of multidisciplinary clinics

The menstrual cycle is a regular natural biological cycle in a woman’s body, during which a mature oocyte (ovum) is released.

The menstrual cycle is a mirror of a woman’s reproductive health, so keeping a menstrual calendar is important.

The menstrual cycle reacts to our entire environment (emotions, mood, stress, sleep, weight fluctuations, etc. ). And most often, rare violations of the cycle are not a problem, but only tell us that we need to take care of ourselves. But frequent and persistent violations can signal probable health problems.

Let’s figure it out.

Four parameters are used to determine normal menstrual bleeding:

• frequency,

• regularity,

• duration,

• vol.

*test* The first day of the menstrual cycle is:

• 1st day of spotting;

• Last day of spotting;

• Day of ovulation.

The normal menstrual cycle in the reproductive period lasts 21-40 days.

If you have fewer than 9 periods a year or cycle more than 21 days, you should consult a gynecologist.

Menstruation does not have to come every day.

Changing the cycle length, i.e. the difference between the shortest and longest cycles depends on age:

• 18 to 25 years – cycle change ≤9 days

• 26 to 41 years – cycle change ≤7 days

• 42 to 45 years – cycle change ≤9 days

Women aged 45 may have more variability.

These age-related fluctuations are associated with the physiological processes of the formation of the menstrual function and its extinction.

The normal number of bleeding days per menstrual cycle is ≤8 days.

There is no consensus on the lower limit of the normal duration of menstruation, since there are no specific pathological formations associated with a short duration.

If menstruation has changed dramatically, consult a gynecologist.

Normal – a volume that does not affect the physical, social, emotional and / or material quality of a woman’s life

Research definition of normal volume – menstrual blood loss ≤80 ml. per cycle

How to understand that menstruation is heavy?

To do this, you need to answer a few questions:

• Do you have your period for more than 8 days?

• do you change hygiene products at night, do you wake up to change hygiene products?

• on days of heaviest bleeding, do your hygiene products get completely wet by 5 drops in 2 hours of use?

• Are there any clots larger than 2 cm?

• Do you have to use 2 hygiene products at the same time to avoid leakage?

• did you have anemia (low hemoglobin)?

• Do you experience weakness, malaise and dizziness during your menstrual days?

• is there a need to organize your life in a special way during menstruation: choose special routes so that you can go to the toilet, refuse long walks or trips, skip events?

If you answered “yes” to at least one question, contact your gynecologist.