Such details help you not to take tests haphazardly, but to choose the right direction for the test.<\/p>\n
When the cause may be anemia<\/h2>\n
Anemia is one of the common causes of constant fatigue. If there is not enough hemoglobin or red blood cells, the tissues receive less oxygen. Because of this, the usual load begins to exhaust faster, weakness, dizziness, shortness of breath, palpitations, pallor, cold hands and feet appear.<\/p>\n
The NHLBI notes that iron deficiency anemia can cause fatigue, shortness of breath, chest pain, headache, restless legs syndrome, and other symptoms, and undiagnosed or untreated anemia can lead to complications.<\/p>\n
You should think about anemia if fatigue is combined with the following symptoms:<\/p>\n
- \n
- pallor;<\/li>\n
- shortness of breath when climbing stairs;<\/li>\n
- palpitation;<\/li>\n
- dizziness;<\/li>\n
- brittle nails;<\/li>\n
- hair loss;<\/li>\n
- coldness in the extremities;<\/li>\n
- heavy menstruation;<\/li>\n
- weakness after light exertion;<\/li>\n
- low ferritin in previous tests.<\/li>\n<\/ul>\n
In such a situation, it may be appropriate to anemia test<\/a>, which helps assess not only hemoglobin, but also possible deficiencies behind weakness.<\/p>\n
When fatigue is related to iron stores<\/h2>\n
Sometimes hemoglobin is still within normal limits, but iron stores are already low. A person may experience fatigue, hair loss, brittle nails, decreased endurance, headaches, or chills. In such cases, it is important to evaluate not only a complete blood count, but also ferritin and other indicators of iron metabolism.<\/p>\n
Ferritin helps to understand how much iron the body has in reserve. If it is low, the cause of fatigue may be related to iron deficiency or anemia, which is why patients often seek, Why are my hands and feet cold and what tests should I take?<\/a>..<\/p>\n
It is especially important to check your iron levels if you have:<\/p>\n
- \n
- heavy or prolonged menstruation;<\/li>\n
- limited nutrition;<\/li>\n
- frequent diets;<\/li>\n
- pregnancy or postpartum period;<\/li>\n
- chronic intestinal diseases;<\/li>\n
- blood in the stool;<\/li>\n
- frequent blood donation;<\/li>\n
- prolonged weakness for no apparent reason.<\/li>\n<\/ul>\n
When to check vitamin B12<\/h2>\n
Vitamin B12 deficiency can manifest itself not only in anemia. It can affect the nervous system, so fatigue is sometimes accompanied by numbness, tingling in the hands and feet, unsteadiness of gait, weakness, and impaired memory or concentration.<\/p>\n
MedlinePlus notes that a B12 deficiency can cause fatigue, lack of energy, dizziness, and numbness and tingling in the hands and feet. Long-term deficiency can lead to nerve damage, so symptoms should not be ignored.<\/p>\n
A B12 test may be appropriate if there is:<\/p>\n
- \n
- constant weakness;<\/li>\n
- numbness or tingling;<\/li>\n
- burning tongue;<\/li>\n
- disequilibrium;<\/li>\n
- memory problems;<\/li>\n
- restrictions on animal products;<\/li>\n
- chronic diseases of the stomach or intestines;<\/li>\n
- taking medications that may affect absorption;<\/li>\n
- anemia of unknown origin.<\/li>\n<\/ul>\n
In such cases, the doctor may prescribe B12, folic acid, a complete blood count, and additional tests depending on the symptoms.<\/p>\n
![\"Laboratory](\"https:\/\/medilab.km.ua\/wp-content\/uploads\/2026\/08\/analizy-pry-slabkosti-ta-vysnazhenni.jpg\")
<\/p>\nWhen fatigue can be a sign of hypothyroidism<\/h2>\n
The thyroid gland affects metabolism, body temperature, heart function, nervous system, skin, hair, and muscles. When its function is reduced, a person may feel not just tired, but generally "slowed down.".<\/p>\n
The American Thyroid Association notes that people with hypothyroidism may experience fatigue, chills, weight gain, dry skin, hair loss, constipation, and other symptoms.<\/p>\n
The following may indicate the benefit of checking the thyroid gland:<\/p>\n
- \n
- drowsiness;<\/li>\n
- frostbite;<\/li>\n
- weight gain for no apparent reason;<\/li>\n
- dry skin;<\/li>\n
- hair loss;<\/li>\n
- puffiness;<\/li>\n
- constipation;<\/li>\n
- menstrual cycle disorders;<\/li>\n
- decreased mood;<\/li>\n
- slow heartbeat.<\/li>\n<\/ul>\n
If fatigue is combined with such manifestations, it is worth evaluating TSH and free T4. You can read more about the meaning of the result in the material about elevated TSH<\/a>.<\/p>\n
When to check glucose<\/h2>\n
Carbohydrate metabolism disorders can also manifest as fatigue. With elevated glucose levels, the body does not always use energy efficiently, and along with this, thirst, frequent urination, hunger, blurred vision, slow wound healing, or frequent infections may occur.<\/p>\n
The CDC lists frequent urination, increased thirst and hunger, fatigue, blurred vision, unintentional weight loss, and frequent infections as symptoms of diabetes.<\/p>\n
Glucose and glycated hemoglobin should be discussed with a doctor if fatigue is combined with:<\/p>\n
- \n
- severe thirst;<\/li>\n
- frequent urination;<\/li>\n
- night trips to the toilet;<\/li>\n
- blurred vision;<\/li>\n
- dry mouth;<\/li>\n
- slow healing of wounds;<\/li>\n
- frequent fungal or urinary infections;<\/li>\n
- a family history of diabetes;<\/li>\n
- weight gain or sudden weight loss.<\/li>\n<\/ul>\n
Glycated hemoglobin helps estimate average glucose levels over the previous months, so it is often used in conjunction with blood glucose.<\/p>\n
When fatigue may be caused by inflammation or infection<\/h2>\n
After an acute infection, weakness may persist for some time. However, if fatigue persists for a long time, is accompanied by fever, night sweats, swollen lymph nodes, joint pain, rash, or weight loss, a closer evaluation is needed.<\/p>\n
MedlinePlus notes that possible causes of fatigue include infections that take a long time to treat or from which the body does not recover immediately, including mononucleosis, hepatitis, tuberculosis, HIV, and other conditions.<\/p>\n
In such a situation, the doctor may prescribe:<\/p>\n
- \n
- complete blood count with leukocyte formula<\/a>;<\/li>\n
- C-reactive protein;<\/li>\n
- ESR;<\/li>\n
- liver tests;<\/li>\n
- tests for specific infections as indicated;<\/li>\n
- urine analysis;<\/li>\n
- additional examinations depending on symptoms.<\/li>\n<\/ul>\n
If fatigue develops after COVID-19 and persists for months, it's also important to assess your overall health. The CDC notes that Long COVID can include fatigue, feeling worse after exercise, brain fog, and many other symptoms that can last for months or years.<\/p>\n
When to evaluate the liver and kidneys<\/h2>\n
The liver and kidneys are involved in detoxification, metabolism, water-salt balance, and many other processes that affect your well-being. Their dysfunction doesn't always start with pain. Sometimes the first symptoms are weakness, decreased endurance, swelling, urine discoloration, itching, nausea, or loss of appetite.<\/p>\n
The NIDDK notes that early stages of chronic kidney disease often have no symptoms, and many people don't notice symptoms until later stages. Blood and urine tests are used to diagnose the condition.<\/p>\n
MedlinePlus describes fatigue as a possible symptom of liver disease, and also indicates that liver disease can cause jaundice, changes in urine and stool color, swelling, and easy bruising.<\/p>\n
For verification you may need:<\/p>\n
- \n
- creatinine;<\/li>\n
- estimated glomerular filtration rate;<\/li>\n
- urea;<\/li>\n
- general urine analysis<\/a>;<\/li>\n
- ALT;<\/li>\n
- AST;<\/li>\n
- bilirubin;<\/li>\n
- alkaline phosphatase;<\/li>\n
- GGT;<\/li>\n
- albumin;<\/li>\n
- electrolytes.<\/li>\n<\/ul>\n
These tests are especially appropriate if fatigue is accompanied by swelling, changes in urine, itching, a yellowish tinge to the skin, and pain or heaviness in the right upper quadrant.<\/p>\n
What tests can help find the cause of fatigue?<\/h2>\n
\n\n
\n Inspection direction<\/th>\n What tests may be needed?<\/th>\n What they help to assess<\/th>\n<\/tr>\n \n Anemia<\/td>\n Complete blood count<\/td>\n Hemoglobin, erythrocytes, leukocytes, platelets<\/td>\n<\/tr>\n \n Iron deficiency<\/td>\n Ferritin<\/a>, iron, transferrin, transferrin saturation<\/td>\n Iron stores and possible deficiency<\/td>\n<\/tr>\n \n B12 or folate deficiency<\/td>\n Vitamin B12, folic acid<\/td>\n Causes of weakness, anemia, tingling, or neurological symptoms<\/td>\n<\/tr>\n \n Thyroid gland<\/td>\n TSH, free T4, antibodies as indicated<\/td>\n Hypothyroidism or other gland dysfunction<\/td>\n<\/tr>\n \n Carbohydrate metabolism<\/td>\n Glucose, glycated hemoglobin<\/a><\/td>\n Risk of diabetes or prediabetes<\/td>\n<\/tr>\n \n Inflammation<\/td>\n C-reactive protein, ESR<\/td>\n Presence of inflammatory activity<\/td>\n<\/tr>\n \n Liver<\/td>\n ALT, AST, bilirubin, GGT, alkaline phosphatase<\/td>\n Possible liver dysfunction<\/td>\n<\/tr>\n \n Kidneys<\/td>\n Creatinine, GFR, urea<\/a>, urine analysis<\/td>\n Kidney filtration function and changes in urine<\/td>\n<\/tr>\n \n Electrolytes<\/td>\n Sodium, potassium, calcium, magnesium<\/td>\n Disorders that can affect weakness and muscles<\/td>\n<\/tr>\n \n Infections<\/td>\n Tests for symptoms and risks<\/td>\n Possible infectious cause of prolonged weakness<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n This list doesn't mean that you should get all the tests done at once. It shows what your doctor might look for if your fatigue is persistent and has no obvious explanation.<\/p>\n
When fatigue requires a faster consultation<\/h2>\n
Most cases of fatigue are not urgent. But there are combinations of symptoms that are best not to be put off.<\/p>\n
See a doctor as soon as possible if you have:<\/p>\n
- \n
- sudden or increasing weakness;<\/li>\n
- dyspnea;<\/li>\n
- chest pain;<\/li>\n
- faint;<\/li>\n
- palpitation;<\/li>\n
- black stools or bleeding;<\/li>\n
- high temperature;<\/li>\n
- night sweats;<\/li>\n
- weight loss for no reason;<\/li>\n
- enlarged lymph nodes;<\/li>\n
- pronounced pallor;<\/li>\n
- severe thirst and frequent urination;<\/li>\n
- swelling;<\/li>\n
- yellowish tinge to the skin or eyes;<\/li>\n
- confusion of consciousness;<\/li>\n
- fatigue after an infection that does not subside for weeks.<\/li>\n<\/ul>\n
In such cases, tests are needed not for reassurance, but to find a cause that may require treatment.<\/p>\n
How to prepare for the inspection<\/h2>\n
Preparation depends on the specific tests. If you are planning to test your glucose, biochemical parameters, or certain hormones, your doctor or laboratory may recommend that you donate blood in the morning or on an empty stomach.<\/p>\n
Before the examination, it is useful to:<\/p>\n
- \n
- write down the main symptoms;<\/li>\n
- note when fatigue began;<\/li>\n
- remember past infections;<\/li>\n
- prepare a list of medications and supplements;<\/li>\n
- report heavy menstruation;<\/li>\n
- talk about diets or dietary restrictions;<\/li>\n
- take preliminary tests;<\/li>\n
- Do not start taking iron, B12, iodine, or hormonal medications on your own before consulting.<\/li>\n<\/ul>\n
If a person is already taking supplements, it is important to inform the doctor. Some of them can affect test results or make interpretation difficult.<\/p>\n
What not to do when you are constantly tired<\/h2>\n
Constant fatigue often makes you look for a quick solution. But there is no universal pill for fatigue, because the causes can be different.<\/p>\n
You should not do it yourself:<\/p>\n
- \n
- take iron without a confirmed deficiency;<\/li>\n
- start thyroid hormones;<\/li>\n
- taking high doses of B12 or folic acid without a plan;<\/li>\n
- blame everything solely on stress;<\/li>\n
- ignore shortness of breath, weight loss, fever, or bleeding;<\/li>\n
- take dozens of tests without understanding the purpose;<\/li>\n
- treat one indicator without a diagnosis;<\/li>\n
- Postpone the consultation if fatigue worsens.<\/li>\n<\/ul>\n
If fatigue lasts for weeks, doesn't go away after sleep, and interferes with your work and life, don't ignore it. This is not the norm, but a reason to talk to your doctor. Start simple: record your symptoms, remember when it all started, and seek help. Your doctor will help you determine what tests are really needed so you don't have to do unnecessary tests, but also don't miss the important ones. Fatigue can be caused by anemia, deficiencies, hormonal changes, problems with glucose, liver, kidneys, or inflammation. And for almost every one of these reasons, there is a treatment or correction that can restore your energy. The main thing is to take the first step.<\/p>","protected":false},"excerpt":{"rendered":"
Chronic fatigue is not the same as normal fatigue after a day at work. It does not go away after a night's sleep, it can<\/p>","protected":false},"author":627,"featured_media":14715,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-14714","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-zahvoryuvannya-ta-symptomy"],"_links":{"self":[{"href":"https:\/\/medilab.km.ua\/en\/wp-json\/wp\/v2\/posts\/14714","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/medilab.km.ua\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/medilab.km.ua\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/medilab.km.ua\/en\/wp-json\/wp\/v2\/users\/627"}],"replies":[{"embeddable":true,"href":"https:\/\/medilab.km.ua\/en\/wp-json\/wp\/v2\/comments?post=14714"}],"version-history":[{"count":3,"href":"https:\/\/medilab.km.ua\/en\/wp-json\/wp\/v2\/posts\/14714\/revisions"}],"predecessor-version":[{"id":14727,"href":"https:\/\/medilab.km.ua\/en\/wp-json\/wp\/v2\/posts\/14714\/revisions\/14727"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/medilab.km.ua\/en\/wp-json\/wp\/v2\/media\/14715"}],"wp:attachment":[{"href":"https:\/\/medilab.km.ua\/en\/wp-json\/wp\/v2\/media?parent=14714"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/medilab.km.ua\/en\/wp-json\/wp\/v2\/categories?post=14714"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/medilab.km.ua\/en\/wp-json\/wp\/v2\/tags?post=14714"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
- complete blood count with leukocyte formula<\/a>;<\/li>\n