For unexplained fatigue, laboratory home tests check the most common measurable causes: ferritin (iron stores), vitamin B12, vitamin D, and TSH (thyroid marker). VitalCheck Complete (capillary blood, €169) measures ferritin, B12, and vitamin D; the TSH self-test checks thyroid function (€14.50). The long-term blood sugar test HbA1c is included in the women’s and men’s health tests; a CRP home test is being prepared. A home test is an initial assessment, not a substitute for a doctor’s visit.
Why fatigue is a question of the right blood markers
Fatigue is a common but nonspecific symptom. It may be harmless or indicate a treatable physical cause. The S3 guideline on “fatigue” issued by the German Society for General and Family Medicine (DEGAM) always places the medical consultation and physical examination first, followed by targeted, limited laboratory testing rather than broad screening.
The blood markers considered include low iron stores (ferritin), a vitamin B12 or vitamin D deficiency, impaired thyroid function (TSH), low-grade inflammation (CRP), and undetected elevated long-term blood sugar (HbA1c). Each of these markers can explain fatigue that does not improve with sleep alone.
A laboratory home test can provide an initial view of some of these markers and thus offer a first objective picture. However, it neither replaces medical assessment nor a complete diagnostic evaluation. The following overview systematically shows why each marker is relevant and where it can be measured as a home test.
The six blood markers for fatigue at a glance
| Blood marker | Why it is relevant to fatigue | Home test at mybody | Sample type | Price | Result |
|---|---|---|---|---|---|
| Ferritin (iron stores) | Iron deficiency is one of the most common measurable causes of fatigue – even without anemia. | Iron-ferritin self-test or VitalCheck Complete | Capillary blood | €14.50 / €169 | Rapid test: minutes / Laboratory: 3–5 business days |
| Vitamin B12 | A deficiency causes exhaustion and difficulty concentrating and can lead to anemia. | VitalCheck Complete | Capillary blood | €169 | Laboratory: 3–5 business days |
| Vitamin D | Low levels are associated with fatigue and muscle weakness. | Vitamin D self-test or VitalCheck Complete | Capillary blood | €14.50 / €169 | Rapid test: minutes / Laboratory: 3–5 business days |
| TSH (thyroid marker) | An overactive or underactive thyroid is a classic cause of persistent fatigue. | Thyroid TSH self-test | Capillary blood | €14.50 | Rapid test: minutes |
| CRP (inflammation marker) | Elevated levels indicate inflammation or infection as the cause of fatigue. | Being prepared as a mybody home test – until then, through a doctor/laboratory | Blood | — | — |
| HbA1c (long-term blood sugar) | Unrecognized high blood sugar (diabetes) can cause persistent fatigue. | Included in the women’s or men’s health test | Capillary blood | €169 | Laboratory: 3–5 business days |
Prices as of July 2026, incl. VAT; subject to change. “Rapid test” = test cassette with results at home; “Laboratory” = sample sent to a partner laboratory. Please check mybody-x.com before purchasing.
The six blood values—and why they matter
Ferritin – the iron store
Ferritin is the storage form of iron in the body. A low ferritin level often indicates iron deficiency earlier than a blood count, sometimes before anemia develops. Iron deficiency is one of the most common physical causes of fatigue, poor concentration, and reduced resilience, especially in menstruating women. Ferritin can be measured with the iron ferritin self-test (€14.50) or as part of the laboratory analysis in the VitalCheck Complete.
Vitamin B12
Vitamin B12 is involved in the formation of red blood cells and the functioning of the nervous system. A deficiency often develops gradually and manifests as exhaustion, concentration problems, tingling in the hands and feet, and a specific form of anemia. Those affected include people following a vegan diet, older adults, and people with gastrointestinal diseases. The level is included in the VitalCheck Complete.
Vitamin D
Vitamin D is produced predominantly in the skin through sunlight. A low level is common during the winter months and when spending little time outdoors. A deficiency is associated with fatigue, muscle weakness, and increased susceptibility to infections. The storage form 25-OH vitamin D3 is measured either with the vitamin D self-test (€14.50) or as part of the VitalCheck Complete.
TSH – the thyroid value
TSH (thyroid-stimulating hormone) is the control hormone that the body uses to regulate the thyroid. An elevated or decreased TSH level indicates an underactive or overactive thyroid—both can cause persistent fatigue, lack of energy, feeling cold, or inner restlessness. The thyroid TSH self-test (€14.50) provides an initial result at home as a capillary blood rapid test. Abnormal results should be confirmed by a doctor, as further values (e.g. fT3, fT4) are needed for diagnosis.
CRP – the inflammation marker
C-reactive protein (CRP) rises during inflammation and infections in the body. A sustained increase can explain why someone feels exhausted and unwell without knowing an obvious cause. A CRP home test is in preparation at mybody; until then, the value should be determined as part of a medical evaluation or through a laboratory—especially because an elevated value must always be interpreted in the context of the symptoms.
HbA1c – long-term blood sugar
The HbA1c value reflects average blood sugar levels over the past approximately eight to twelve weeks. Previously undetected high blood sugar (prediabetes or diabetes) may initially manifest only as fatigue, thirst, and frequent urination. At mybody, HbA1c is included in the more comprehensive health tests—the Women's Health Test and the Men's Health Test (capillary blood, €169 each), which cover additional values such as a blood count and thyroid function alongside long-term blood sugar. An abnormal result should be medically evaluated, as a diabetes diagnosis entails specific treatment steps.
What these tests cannot do
A home laboratory test is a preliminary assessment, not a substitute for a doctor's visit. These limitations are crucial before making a purchase decision:
Persistent fatigue should be medically evaluated. The S3 guideline “Fatigue” places the medical history and physical examination first. If fatigue persists for several weeks, no home test can replace this assessment.
Home tests cover only some of the possible causes. The individual rapid tests and the VitalCheck Complete contain neither CRP nor HbA1c; long-term blood sugar is covered only by the more comprehensive women's and men's health tests, while a CRP home test is in preparation. Blood tests do not detect psychological causes, sleep disorders, medication effects, or sleep apnea either.
A single value is only one piece of the puzzle. Abnormal or borderline results from rapid tests should be confirmed by a laboratory test performed by a doctor (venous blood) before starting dietary supplements or treatment.
Seek immediate medical attention if you experience warning signs. These include unintentional weight loss, fever or night sweats, shortness of breath, severe pallor with dizziness, blood in the stool, and fatigue that is rapidly worsening.
Testing, laboratory, and data protection
- Order the appropriate test online (free shipping on orders over €49).
- Collect a drop of blood from your fingertip at home. Takes around 10 minutes.
- Receive your result: The TSH self-test displays the result on a test cassette directly at home; the laboratory analysis (e.g. VitalCheck Complete) is sent in pseudonymized form.
- Laboratory analyses are evaluated in an ISO-certified laboratory in Germany. Data processing is certified according to ISO/IEC 27001 (information security standard).
- Access laboratory results in the online portal: Blood tests after 3–5 working days.
- Data protection: Processing is carried out in compliance with the GDPR.
Frequently asked questions
Which test is the first sensible step for fatigue?
It is often useful to check ferritin, vitamin B12, and vitamin D—these values are covered by VitalCheck Complete in a laboratory analysis. If there is also suspicion of a thyroid problem, the TSH self-test can be added. If fatigue persists for a longer period, medical advice should be sought in parallel.
Can a home test reliably determine the cause of my fatigue?
No. A home test is an initial assessment. It can reveal individual blood values, but it does not replace medical diagnosis, which also takes medical history, physical examination, and additional values into account.
Can I also test CRP and HbA1c at home?
Long-term blood sugar (HbA1c) is included in the more comprehensive health tests for women and men (capillary blood, €169 each). A CRP home test is in preparation at mybody; until then, CRP is measured by a doctor or through a laboratory. Abnormal results should always be assessed by a doctor.
What does my ferritin level indicate about my fatigue?
Ferritin reflects the body's iron stores. A low level indicates iron deficiency, one of the most common physical causes of fatigue—often before anemia becomes apparent. An abnormal result should be assessed by a doctor.
How quickly will I get a result?
The rapid tests (e.g. TSH, vitamin D, ferritin) show the result on a test cassette at home within minutes. The VitalCheck Complete laboratory analysis is available in the online portal after 3–5 working days.
Should I keep anything in mind before the test?
Follow the instructions in the test kit, for example regarding the time of day and hand hygiene. If you are taking dietary supplements or medication, it is advisable to consider this when interpreting the results and discussing them with a doctor.
When should I see a doctor about fatigue?
At the latest when the fatigue persists for several weeks, significantly restricts daily life, or is accompanied by warning signs such as unintentional weight loss, fever, shortness of breath, or blood in the stool. In that case, medical evaluation takes priority.
Does the nutrient analysis replace a blood count at the doctor’s office?
No. The analysis measures specific nutrient and metabolic values, but not a complete blood count or inflammatory or blood sugar values such as CRP and HbA1c. Medical laboratory diagnostics remain essential for a complete assessment.
Sources
- German Society for General and Family Medicine (DEGAM): S3 Guideline on Fatigue, AWMF Register No. 053-002, as of January 2023.
- World Health Organization (WHO): WHO guideline on use of ferritin concentrations to assess iron status in individuals and populations, 2020.
- German Nutrition Society (DGE): Reference values for vitamin D intake, 2012 edition.
- Pearce SHS et al. for the European Thyroid Association (ETA): 2013 ETA Guideline: Management of Subclinical Hypothyroidism, European Thyroid Journal 2013;2(4):215–228.
Choose the right test
For ferritin, vitamin B12, and vitamin D in a single laboratory analysis—or specifically for the thyroid value:
