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.

How to Diagnose High Potassium Levels

Potassium is a nutrient in food that helps your body run smoothly. Too much potassium in your body can cause health problems, but a simple blood test can measure your levels.

Potassium plays a role in letting your muscles and nerves signal each other, keeps fluid levels balanced in your body, and helps you have a regular heartbeat. Your potassium levels might get high if your kidneys aren’t working well.

A normal blood potassium level for adults is between 3.5 and 5.5 millimoles per liter (mmol/L).  

A potassium level above 5.5 mmol/L is high. Above 6.5 mmol/L is dangerously high and means you need medical care right away.

Symptoms of High Potassium

You often don’t notice any symptoms from high potassium levels. You might first learn about it when you get the results of a routine blood test.

If you do get symptoms, they may come and go and might include:

• Stomach pain
• Diarrhea
• Fatigue
• Chest pain
• Irregular heartbeat that may feel fast or like a fluttering sensation
• Muscle weakness
• Numbness or paralysis in your arms or legs
• Nausea or vomiting

Check with your doctor if you have any of these symptoms, especially if you have kidney disease or take a medication that can raise your potassium level.

Blood Test for High Potassium

Your doctor will check your potassium level during your annual physical exam. If you have a health condition such as diabetes or kidney disease, they may test your potassium level more regularly. They will also see if you have symptoms of high potassium, high blood pressure, or signs of a heart problem.

To check for high potassium, you get a blood test which measures the amount of potassium in your blood. The doctor puts a small needle into a vein in your arm and takes out a small amount of blood. You might feel a slight pinch or sting when the needle goes in.

Your doctor sends the blood sample to a lab, where technicians test the level of potassium in the liquid part of your blood (serum). Your doctor will let you know the results.

It’s not uncommon to have a false high potassium test result, which happens when blood cells rupture during the blood draw. They leak more potassium into your blood, making it seem like your level is high. Your doctor may repeat the test before treating you for high potassium.

If your doctor is concerned that you may be having a problem with your heart, they may also ask you to get a test called an electrocardiogram (EKG) to see if your heart is beating normally.

SOURCES:

American Association of Kidney Patients: “High Potassium (Hyperkalemia) Information.”

Medline Plus: “Potassium Blood Test.”

American Kidney Fund: “What is High Potassium or Hyperkalemia?”

Cleveland Clinic: “Hyperkalemia: High Potassium,” “High Potassium (hyperkalemia): Diagnosis and Tests.”

Mayo Clinic: “High Potassium (hyperkalemia).”

UCSF Health: “Potassium Test.”

StatPearls: “Hyperkalemia.”

Human Hearing Characteristics – Hearing Thresholds and Ranges

Hearing threshold

The human hearing threshold is the minimum level of sound that a person can perceive. This characteristic is one of the main ones.

Hearing sensitivity depends on the hearing threshold: the lower the hearing threshold, the higher the hearing sensitivity, and vice versa. The range of the highest sound sensitivity is from 1000 to 4000 Hz. It is in this interval that information about speech signals is located. Hearing thresholds at 200 Hz are 35 dB higher and at 100 Hz are 60 dB higher than hearing thresholds at 1000 Hz.

The normal hearing threshold is between -10dB and +10dB. In cases of hearing impairment, the thresholds can be different – from 20 to 120 dB.

Source: introduction to audiology and hearing aid I.V. Queen

Discomfort threshold

The threshold of discomfort is the level of sound that causes discomfort in a person. The norm is 100-110 dB, and it depends not only on the state of the hearing organ, but also on the excitability of the nervous system as a whole. In patients with hearing impairments, the discomfort threshold is usually greater than 110 dB. However, many people with sensorineural hearing loss have thresholds of discomfort that are the same as those of people with normal hearing or lower – a phenomenon called recruitment, or the “amplifying loudness phenomenon. ”

Pain threshold

Pain in the organ of hearing, as a rule, causes a sound of 130-140 dB. In addition, one should distinguish between the threshold of touch and the pain threshold – in the first case, a person feels only pressure on the eardrum (130 dB), in the second – already pain sensations (140 dB). The threshold of discomfort for people with hearing impairment may differ from the norm, but the pain threshold is always the same for everyone.

Hearing frequency range

The ability to perceive sounds in the frequency range from 20 to 20,000 Hz is considered the norm for a person. Sounds with a frequency above 20,000 Hz are called ultrasonics, and those below 20 Hz are called infrasounds. A person can perceive ultrasound only if its source is applied to the bones of the skull – this property is sometimes used in the diagnosis of hearing impairment.

Source: introduction to audiology and hearing aid I.V. Queen

Approaching the study of hearing, the sound frequency range is conventionally divided:

to low frequencies – up to 500 Hz;

at medium frequencies – 500-3000 Hz;

to high frequencies – 3000–8000 Hz;

for ultra-high frequencies – above 8000 Hz

Hearing dynamic range

The dynamic range of hearing is the total amount of sound levels that a person is able to perceive, normally it is 130 dB. The difference between the quietest and loudest sound perceived by the human ear (up to palpable or pain thresholds) is large – the latter is higher by about 10 ¹³ times.

In audiology, the dynamic range of hearing is the range from a person’s hearing threshold to their discomfort threshold.

Both dynamic and frequency range can be different for people with hearing loss.

Differential hearing threshold

The minimum differences in frequency, intensity, or duration of a sound perceived by human hearing are called the differential hearing threshold.

It is the ability to detect minimal differences between sounds that allows us to perceive speech. The intensity and frequency of the differential hearing threshold depends on the duration, level and frequency of the sound. The norm for a person is 1–1.5 dB in intensity at frequencies of 500–4000 Hz at a sound level of 40 dB.

The reason for the poor perception of speech by people with hearing impairment lies in the increase in their differential hearing threshold – they simply cease to perceive small differences between speech sounds.

Binaural hearing

The ability of a person to perceive sound with two ears and process the received signals in the corresponding symmetrical auditory centers of the brain is called binaural hearing. This property provides the so-called process of binaural fusion – this is when sounds of different characteristics entering the right and left ears of a person are perceived by the human auditory system as a single and integral auditory image. In addition, by comparing the sounds entering the right and left ears, the auditory system determines where the sound source is.

It is binaural hearing that allows us to perceive speech in noisy environments – the so-called “binaural release from disguise” effect occurs.

Article about binaural prosthetics.

Source: introduction to audiology and hearing aid I.V. Queen

Hearing adaptation

Like other sensory systems of the human body, the auditory system is able to adapt to external conditions. This is manifested in a temporary decrease in sensitivity due to an increase in hearing thresholds in cases of excessive sound exposure. With this ability, the auditory system protects itself from damage.

The hearing threshold is raised by any exposure to sound that exceeds this threshold by 10-20 dB. In cases of short-term exposure to sound no higher than 80-90 dB, and the increase in the threshold will be short-term. With more intense exposure, the increase in hearing thresholds will last longer – up to several minutes. After the cessation of sound exposure, the hearing thresholds gradually return to their original state.

Blood pressure – norm and pathology

from May 14 to 24 as part of the Year of the Heart at the MUSIC City Hospital No. 1

im. G.I. Drobyshev is holding an information and practical campaign

“Learn to control your blood pressure.”

One of the most common health complaints and one of the “favorite” diseases in the elderly is high blood pressure. This pathology can explain any changes in well-being, bad mood and other troubles. Blood pressure can rise and fall several times during one day, and a person’s normal pressure is a purely individual concept.

What is blood pressure and what values ​​are considered normal?

Blood pressure is a general concept that determines the force with which blood presses on the walls of blood vessels, it is more correct to call it blood pressure, because pressure is important not only in arteries, but also in veins and capillaries. But it is possible to measure without the help of special instruments only the pressure in large vessels located on the surface of the body – in the arteries.

Blood pressure – BP – depends on how fast and force the human heart contracts, how much blood it can pump in one minute, on the properties of the blood itself and the resistance of the vessel walls.

Factors affecting the magnitude of blood pressure:

• the ability of the heart to contract with sufficient force and ensure a normal ejection of blood through the vessels;
• from the rheological properties of blood – the “thicker” the blood, the more difficult it is to move through the vessels, diseases such as diabetes mellitus, increased clotting, greatly impede blood flow and can lead to problems with blood pressure, with thick blood, some doctors prescribe treatment with leeches ;
• elasticity of vessel walls – blood vessels wear out over time and cannot withstand increased stress – this causes the development of hypertension in the elderly,
• atherosclerotic changes – reduce the elasticity of the walls;
• sudden constriction or dilation of blood vessels – as a result of nervous shocks or hormonal changes, a sharp narrowing or expansion of blood vessels is possible – for example, with fear, anger or other strong emotions;
• diseases of the endocrine glands.

Normal pressure is determined by a combination of a large number of parameters, and for each age, gender and for an individual, its indicators can vary greatly. For medical norms, average indicators are taken from healthy people of a certain age. It has long been proven that a pressure of 120/80 cannot and should not be considered the ideal norm for people of different ages.

To find out what normal pressure a person should have at different age periods, you can use the following table.

Adult blood pressure readings:

• Normal blood pressure is considered to be between 110/70 and 130/85 mm. rt. Art.
• Reduced normal pressure – 110\70 – 100\60;
• Low blood pressure – hypotension – below 100/60;
• Increased normal pressure – 130\85-139\89;
• High blood pressure – hypertension – more than 140\90 mm. rt. Art.

Indicators of normal blood pressure for different age periods:

• 16 – 20 years old – 100\70 – 120\80 mm. rt. Art.
• 20 – 40 years – 120\70-130\80;
• 40 -60 – up to 140\90;
• over 60 years old – up to 150\90 mm. rt. Art.

From the table above, it can be seen that the greater the age of a person, the higher the normal blood pressure, this is due to age-related changes in blood vessels, in the heart muscle and in other organs. High blood pressure, as well as low blood pressure, can cause various health problems, but in order to determine whether a change in the level of pressure is to blame for feeling unwell, it is necessary to regularly measure it and keep a special diary. For this, several trips to the clinic or visits to the doctor are not enough, only daily regular pressure measurements can give the correct results.

Measurement.

The correctness of the diagnosis and prescription of treatment largely depends on the correct measurement of blood pressure, because the doctor, prescribing a medicine or prescribing treatment, largely focuses on the measurement numbers.

Today there are different ways to measure pressure:

1. The simplest and oldest – with the help of a cuff and a tonometer – it is of great importance to correctly apply the cuff, the ability to use a tonometer and listen to heart sounds. Such a measurement requires special training and skills, but when used correctly, it gives fairly accurate and reliable results.
2. Electrotonometer – the principle of operation is the same, but the results are visible on a special display. This facilitates self-measurement of pressure and provides more accurate results. But such blood pressure monitors often break down and may show incorrect numbers.

No matter how blood pressure is measured, some general rules must be observed:0110

measurement should be carried out on both hands and it is desirable to carry out a series of measurements with an interval of 5-10 minutes.

If, after a correct measurement of blood pressure, the readings are very different from the norm, it is necessary to repeat the measurements within a few days and, if confirmed, consult a doctor.

High blood pressure.

Considered one of the most dangerous diseases of mankind, about 25% of people worldwide suffer from hypertension, and this figure continues to increase. Hypertension is an increase in blood pressure above 140/90 mm. rt. Art. The causes of hypertension can be:

• overweight,
• genetic predisposition,
• diseases of internal organs,
• lack of physical activity,
• smoking and drinking,
• excessive consumption of table salt,
• nervous strain,
• other factors.

With hypertension, the patient suffers from headaches (and here headache pills will not help), shortness of breath, pain in the heart, increased fatigue, insomnia, poor health and other symptoms. In addition, the risk of developing cardiovascular diseases, brain damage, pathology of the urinary system and eye diseases increases.

The treatment of hypertension is a very complex and time-consuming process, where the outcome of diseases depends on compliance with the doctor’s recommendations. It is important to find the cause of the increase in pressure and act on it. At the same time providing symptomatic treatment. In each case, drugs, doses and their combination should be selected individually by the attending physician.

Without timely treatment or uncontrolled use of drugs, hypertension can not only severely damage health, but also cause such a life-threatening condition as a hypertensive crisis.

Hypertensive crisis.

Hypertensive crisis is a life-threatening condition caused by a sharp increase in blood pressure and damage to the nervous system and target organs. The blood pressure figures in a hypertensive crisis can vary greatly in different patients – someone normally tolerates 200\150 mm. rt. st, and someone feels bad already at 150 \ 85 mm. rt. Art. The nature of the lesions in GC depends on the organs in which the pathology was previously – if the heart hurt, myocardial infarction may occur, if it was tormented – headaches – then a stroke, and so on.

The causes of GC can be:

• psycho-emotional overstrain,
• physical activity,
• meteorological changes,
• drinking alcohol,
• rich food with high salt content,
• improperly selected antihypertensive drugs,
• diseases of the endocrine system and internal organs.

With the development of GC, the patient’s state of health deteriorates sharply, there is a feeling of fear, anxiety, nausea, vomiting, darkness before the eyes, swelling and flushing of the face, chills, tremor of the extremities, fainting, up to coma.

If these symptoms appear, the patient should be placed on any flat surface with a raised headboard and an ambulance should be called immediately. Before her arrival, try to provide the patient with peace, an influx of fresh air, get rid of tight clothing, if the patient has had hypertension for a long time, then most likely he is taking some kind of antihypertensive drug, in this case, you can give the patient the usual dosage before arrival.

Hypotension, low blood pressure.

For many people, especially those suffering from hypertension, it seems that lowering blood pressure may not be a problem, but in fact it is not. Constantly low blood pressure can cause no less inconvenience and cause health problems than hypertension.

The causes of this pathology can be hereditary predisposition, poor nutrition and beriberi, endocrine diseases, nervous strain, general exhaustion of the body and other problems.

A person suffering from hypotension constantly feels tired, overwhelmed, he hardly performs daily duties and is emotionally retarded. In addition, there is a decrease in memory and brain activity, poor thermoregulation, increased sweating, headaches, drowsiness, pain in the joints and muscles, and a general deterioration in well-being.