biology

Hemoglobinemia

Hemoglobinemia is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Hemoglobinemia rather than just read about it. In short: Hemoglobinemia (or haemoglobinaemia) is a medical condition in which there is an excess of hemoglobin in the blood plasma. This is an effect of intravascular hemolysis, in which hemoglobin separates from red blood cells, a form of anemia.

Key takeaways

Hemoglobinemia belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Hemoglobinemia to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Hemoglobinemia from memory before moving on to harder problems.

Reference excerpt

Hemoglobinemia (or haemoglobinaemia) is a medical condition in which there is an excess of hemoglobin in the blood plasma. This is an effect of intravascular hemolysis, in which hemoglobin separates from red blood cells, a form of anemia. Hemoglobinemia can be caused by intrinsic or extrinsic factors. When hemoglobinemia is internally caused, it is a result of recessive genetic defects that cause the red blood cells to lyse, letting the hemoglobin spill out of the cell into the blood plasma. In intravascular hemolysis, hemoglobin is released and binds with haptoglobin. This causes haptoglobin levels to decrease. Once haptoglobin is saturated, free hemoglobin readily distributes to tissues where it might be exposed to oxidative conditions. In such conditions, heme can be released from ferric hemoglobin. The free heme can then accelerate tissue damage by promoting peroxidative reactions and activation of inflammatory cascades. Hemopexin (Hx) is another plasma glycoprotein able to bind heme with high affinity. Hx sequesters heme in an inert, non-toxic form and transports it to the liver for catabolism and excretion. As long as both haptoglobin and hemopexin are saturated, the remaining free hemoglobins are filtered in the kidney and some of them will be reabsorbed by way of proximal tubules. In externally caused hemoglobinemia, an outside attacker acts as an antibody against the red blood cells. This can cause the cells to be destroyed and their hemoglobin released. In extravascular hemolysis, red blood cells are phagocytized by macrophages in the spleen and liver. Abnormal value of hemoglobin does not necessarily indicate a medical problem needing treatment. Diet, activity level, medications, a women's menstrual cycle, and other considerations can affect the results. Additionally to these, one may have higher than normal hemoglobin if they live in a high altitude area.

Causes There are other causes besides what happens within the body in the blood cells. Other factors that can cause an excess amount of hemoglobin are:

Smoking (which may result in low blood oxygen levels) Higher altitudes where your red blood cell production naturally increases to compensate for the lower oxygen supply there Specific disorders or other factors that may cause a high hemoglobin count include:

Lung disease Heart disease COPD (chronic obstructive pulmonary disease) Dehydration Emphysema Heart failure Kidney cancer Liver cancer Other types of heart disease Other types of lung disease Polycythemia vera, a disorder in which your body makes too many red blood cells. It can cause headaches, fatigue, and shortness of breath.

Diagnosis

Normal hemoglobin levels Normal hemoglobin levels correlate with the person's age and sex. Levels can vary between different testing systems and under their doctor's consultation. A hemoglobin test measures the amount of hemoglobin in your blood. If a hemoglobin tests shows that a person's levels are below normal, it means they have a low red blood cell count, which is known as anemia. If the test shows higher levels than normal, it means they have hemoglobinemia. The normal range for hemoglobin is:

For men, 13.5 to 17.5 grams per deciliter. 13.5 and 18 g/dl are the lower and upper limits of the acceptable range. For women, 12.0 to 15.5 grams per deciliter 12 and 16 g/dl are the lower and upper limits of the acceptable range.

Treatment High hemoglobin levels are a rare occurrence but is usually treated as a symptom for an underlying disease. Consulting a doctor is the best treatment, so they can diagnose your illness and give a recommended treatment plan to lower hemoglobin levels back to normal.

See also Coagulation Blood diseases Methemoglobinemia, an abnormal amount of methemoglobin which is carrying oxygen but unable to release it effectively to body tissues, is produced.

References "Hemolytic Anemia". University of Virginia Health System. Retrieved 2009-05-01.

Illustrations

Worked examples

Example 1 — a first encounter with Hemoglobinemia

Start with the simplest possible case. Write down what Hemoglobinemia claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Hemoglobinemia before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Hemoglobinemia ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Hemoglobinemia

In research: Hemoglobinemia appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Hemoglobinemia in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Hemoglobinemia is common in secondary-school and first-year university syllabi. It links to neighbouring topics Rare diseases, Red blood cell disorders, so understanding it makes those chapters shorter.
In everyday life: Look for Hemoglobinemia outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Hemoglobinemia in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Hemoglobinemia means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Hemoglobinemia out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Hemoglobinemia in simple terms?

Why does Hemoglobinemia matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Hemoglobinemia?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Hemoglobinemia.