Blood count and blood group · Blood

Hemoglobin (Hb)

The red blood pigment that carries oxygen; the standard measurement for diagnosing anemia.

At a glance

Measured in blood
In 18 test panels
No special preparation

Explanation

Hemoglobin (Hb): what is measured?

Hemoglobin is the iron-containing protein in the red blood cells that binds oxygen from the lungs and carries it to all tissues. The test measures how much hemoglobin there is per liter of blood. With a shortage, the tissues get less oxygen; this is called anemia. Hemoglobin is always assessed together with the other values of the blood count, especially the MCV and the ferritin.

What can it detect?

Anemia, usually due to iron deficiency, sometimes due to a shortage of vitamin B12 or folic acid
Anemia with a chronic disease, a recent infection or a kidney disease
Too much hemoglobin (polycythemia), for example due to smoking, a lung disease or dehydration

Result

What does the result mean?

Hemoglobin (Hb) too high

A raised hemoglobin is usually due to the blood becoming more concentrated with dehydration, for example after drinking little, exercising or hot weather. Other causes are smoking, a lung disease with too little oxygen, sleep apnea or a longer stay at high altitude; the body then makes extra red blood cells. Use of testosterone or anabolic substances also raises the hemoglobin. Rarely, the cause lies in the bone marrow itself (polycythemia vera), a rare condition in which too many red blood cells are made. There are often no symptoms; sometimes headache, a red face or itching after a warm shower.

Hemoglobin (Hb) too low

A low hemoglobin means anemia. According to the Dutch GP guideline (NHG), the cutoff is 8.5 mmol/l for men and 7.5 mmol/l for women; different limits apply to pregnant women and children. The most common cause is iron deficiency, in women often due to heavy periods and in people over 50 more often due to unnoticed blood loss from the stomach or bowel. Other causes are a shortage of vitamin B12 or folic acid, a chronic disease or inflammation, an infection in the past month, a kidney disease or a hereditary hemoglobin disorder such as thalassemia. Symptoms that go with it: tiredness, shortness of breath on exertion, dizziness, palpitations, paleness and ringing in the ears; mild anemia often causes no symptoms.

After an abnormal result

With a low hemoglobin, according to the Dutch GP guideline (NHG), the GP always has the MCV and the ferritin measured and, if needed, vitamin B12, folic acid, reticulocytes, kidney function or testing for hereditary hemoglobin disorders; only in women with heavy periods can this be skipped. With iron deficiency over the age of 50, examination of the stomach and bowel usually follows to rule out blood loss. A raised hemoglobin is usually repeated after drinking well; if it stays high, testing into the cause follows.

Reliability

How reliable is the test?

A hemoglobin measurement in the laboratory is accurate and repeatable; a value below the cutoff establishes anemia, but says nothing about the cause. That is why the Dutch GP guideline (NHG) has the GP always measure the MCV and the ferritin with a low Hb. Values right around the cutoff can fluctuate slightly from day to day, partly due to the amount of fluid in the blood. Reference values differ by age, sex and laboratory.

What can affect the result?

Dehydration raises the hemoglobin; drinking a lot, an IV drip or a pregnancy lowers it, without the number of red blood cells changing.
After an infection in the past month, the hemoglobin can be temporarily lower; the NHG guideline then advises a check four weeks after recovery.
In carriers of thalassemia or sickle cell anemia, a slightly low Hb with a low MCV is normal and not a sign of iron deficiency.
A blood donation in the weeks before the blood draw temporarily lowers the hemoglobin; smoking and use of testosterone or anabolic substances raise it.

Who it is for

Who is the test useful for?

Useful for

Useful with symptoms that fit anemia (tiredness, shortness of breath on exertion, dizziness, palpitations, paleness), with heavy periods, after a pregnancy, with a vegetarian or vegan eating pattern, with chronic diseases and for monitoring previously diagnosed anemia. In healthy adults without symptoms or risk factors, the chance of an abnormal result is small; a chance slightly abnormal value is then often due to not drinking enough or a fluctuating fluid balance and mainly leads to extra testing.

How common is it?

In Dutch general practice, anemia is newly diagnosed in about 9 in 1000 people per year, in half of them due to iron deficiency; women are diagnosed about four times as often as men, especially between 15 and 50 years of age. At older age, a chronic disease is often the cause alongside iron deficiency. Too much hemoglobin due to a bone marrow disease is rare.

The NHG guideline on anemia (M76)

Drawbacks and risks

A slightly raised Hb is often due to not drinking enough before the blood draw, and a slightly low Hb with heavy periods is usually harmless iron deficiency; without that context, the result easily leads to unnecessary worry.
A normal hemoglobin does not rule out early iron deficiency: the iron stores (ferritin) fall before the Hb does.

Get tested

Hemoglobin (Hb): test panels

Hemoglobin (Hb) is part of these test panels. You order online and have your blood drawn at a collection point or collect the sample at home.

Blood draw
Vegan Test
Panel for vegetarian or vegan diet; B12 D iron and more.
€ 116,00
Blood draw
General Health Checkup
With this General Health Check-up, you gain detailed insight into your overall health and well-being.
€ 125,00
Blood draw
Blood Count
Blood Count; complete analysis of blood cells for detection of anemia and infections.
€ 19,00
Blood draw
Complete Blood Count (CBC)
Complete Blood Count Extended; standard blood count plus detailed white blood cell analysis.
€ 27,00
Blood draw
InsideTracker
InsideTracker Blood Analysis: analyze 48 biomarkers for complete health optimization and personalized recommendations.
€ 335,00
Blood draw
Testosterone Replacement Therapy (TRT)
Testosterone, LH, FSH, Oestradiol, Prolactin, liver function, and blood values. For men with low testosterone or TRT monitoring.
€ 175,00
Blood draw
Endurance Sports
Complete blood count, iron status (ferritin, transferrin), kidney function, liver function, testosterone, and hs-CRP. For athletes and endurance sport participants.
€ 203,00
Blood draw
Vegetarian Extensive
Iron, ferritin, B12 total and active, vitamin D, folic acid, zinc, magnesium, hemoglobin, and hematocrit. Complete nutritional status check.
€ 269,00
Blood draw
General Blood Test (Basic)
Hemoglobin, MCV, TSH, fT4, eGFR, creatinine, ALT, AST, sodium, and potassium. General health check of kidney, liver, and thyroid.
€ 125,00

How reliable is the test?

Hemoglobin (Hb)