Hemoglobin 19.8 g/dL: Is That High?

Is Hemoglobin 19.8 g/dL Low, Normal, or High?

Hemoglobin 19.8 g/dL is above the normal range and is considered elevated. The standard hemoglobin range is 12.5 to 17.5 g/dL, placing 18.5 above the upper limit. Hemoglobin is the oxygen-carrying protein in your red blood cells, and having too much of it can be a concern just as having too little can. An elevated hemoglobin level means your blood contains more red blood cells or more concentrated hemoglobin than typical, which can make your blood thicker and harder to circulate. This condition is generally referred to as polycythemia. While there are benign explanations for mildly elevated hemoglobin, this result warrants investigation by your doctor to determine the cause.

A hemoglobin level of 19.8 g/dL is significantly elevated, signaling a condition known as polycythemia, where the body produces an excess of red blood cells. At this specific degree of elevation, common causes typically include chronic conditions that lead to low oxygen levels, such as severe lung disease (e.g., advanced COPD) or prolonged residence at high altitudes, as the body attempts to compensate. A primary concern for a level this high is also a myeloproliferative neoplasm, most notably Polycythemia Vera, a bone marrow disorder characterized by the overproduction of red blood cells. Further investigation usually involves a detailed clinical history and physical examination, alongside blood tests like erythropoietin levels, which help distinguish between primary and secondary causes. Genetic testing for the JAK2 mutation is often crucial for diagnosing Polycythemia Vera. Depending on initial findings, imaging of the kidneys or lungs and a referral to a hematologist or pulmonologist would be standard next steps. While a hemoglobin of 19.8 g/dL warrants prompt investigation, many patients with elevated hemoglobin can lead full, active lives with appropriate management. This increased red blood cell count thickens the blood, however, potentially raising the risk of blood clots. Consistent monitoring and adherence to treatment plans—which might involve therapeutic phlebotomy or medications—are therefore vital to prevent serious complications.

Hidden Risk of Hemoglobin 19.8 g/dL

A hemoglobin of 19.8 g/dL may not cause noticeable symptoms right away, but elevated hemoglobin carries risks that are important to understand. When your blood is thicker than normal, it moves more slowly through your vessels, and this can create problems in your circulatory system. The American Society of Hematology notes that persistently elevated hemoglobin increases the risk of several serious complications.

A hemoglobin level of 19.8 g/dL significantly increases blood viscosity, making the blood thicker and more sluggish. This heightened viscosity raises the risk of developing blood clots, particularly in smaller vessels, which can lead to serious conditions such as deep vein thrombosis (DVT), pulmonary embolism (PE), or even strokes and heart attacks. The increased workload on the heart to pump this thicker blood can also strain the cardiovascular system, potentially exacerbating or unmasking underlying heart conditions. Furthermore, the tendency for hypercoagulability at this elevated level poses a danger during any surgical or invasive procedures.

Risks associated with hemoglobin at 19.8 g/dL include:

• Blood clots, including deep vein thrombosis (DVT) in the legs and pulmonary embolism in the lungs
• Increased risk of stroke due to thickened blood moving through small vessels in the brain
• Heart attack risk rises because the heart has to work harder to pump thicker blood
• Headaches, dizziness, and blurred vision caused by sluggish blood flow to the brain
• High blood pressure, as thicker blood creates more resistance in the arteries
• Itchy skin, particularly after a warm shower or bath, which is a classic symptom of polycythemia vera
• Gout caused by elevated uric acid levels, which can occur when excess red blood cells break down

What Does a Hemoglobin Level of 19.8 g/dL Mean?

Hemoglobin is the oxygen-carrying protein inside your red blood cells. Each hemoglobin molecule picks up oxygen in your lungs and delivers it to cells throughout your body. When hemoglobin is measured at 19.8 g/dL, it means there is more of this protein in your blood than the body typically needs. While it might seem like more oxygen delivery would be a good thing, too much hemoglobin actually creates problems. Thicker blood does not flow as smoothly, and the increased viscosity can slow circulation, raise blood pressure, and increase the risk of clotting. The National Institutes of Health identifies several possible reasons for elevated hemoglobin. The most common is dehydration, which temporarily concentrates your blood and can make hemoglobin appear higher than it truly is. Living at high altitude is another common cause, as your body produces more red blood cells to compensate for lower oxygen levels in the air. Smoking can also raise hemoglobin because carbon monoxide from cigarettes reduces the oxygen-carrying efficiency of each hemoglobin molecule, prompting your body to make more. Chronic lung diseases like COPD can have a similar effect. In some cases, elevated hemoglobin points to polycythemia vera, a bone marrow disorder where the body produces too many red blood cells. Less common causes include kidney tumors, testosterone use, and certain performance-enhancing drugs. Your doctor can use additional tests to determine which category your elevation falls into.

A hemoglobin reading of 19.8 g/dL is most likely attributable to significant dehydration, where a reduction in plasma volume concentrates the red blood cells. Another strong possibility is chronic hypoxia, such as that experienced by individuals living at high altitudes or suffering from severe lung disease, prompting the body to overproduce red blood cells as a compensatory mechanism. Certain tumors, particularly renal cell carcinoma or hepatocellular carcinoma, can also secrete erythropoietin, driving excessive red blood cell production leading to such high levels.

Lifestyle Changes for Hemoglobin 19.8 g/dL

If your hemoglobin is elevated at 19.8 g/dL, certain lifestyle adjustments can help manage your levels while your doctor works to identify the cause. Hydration is the single most important factor. Dehydration concentrates your blood and raises hemoglobin readings, so drinking plenty of water throughout the day, especially in warm weather or during exercise, is essential. Aim for at least eight glasses of water daily, and more if you are physically active or live in a hot climate. If you smoke, quitting is strongly recommended. Smoking is one of the most common causes of elevated hemoglobin, and the Mayo Clinic lists smoking cessation as a key step in managing high hemoglobin. Your body produces extra red blood cells to compensate for the carbon monoxide in cigarette smoke, and stopping allows hemoglobin to normalize over time. Regular moderate exercise helps maintain cardiovascular fitness, but avoid extreme endurance training at high altitudes, as this can further stimulate red blood cell production. If you live at high elevation, be aware that some degree of elevated hemoglobin is a natural adaptation, but discuss with your doctor what level is safe for you. Avoid very hot baths and saunas if you experience itchy skin, as heat can worsen this symptom. Be mindful of any supplements or substances that might increase red blood cell production, including anabolic steroids or testosterone, and discuss these with your doctor.

With a hemoglobin value of 19.8 g/dL, immediate medical attention is warranted. Focus on rehydration by increasing fluid intake significantly, aiming for clear, non-caffeinated liquids. A follow-up complete blood count (CBC) with differential should be scheduled within 24-48 hours to assess if the level is trending downwards. If the elevated level persists after rehydration, a referral to a hematologist is crucial to investigate the underlying cause, which may involve specialized blood tests and imaging studies to rule out conditions like polycythemia vera or secondary causes of erythrocytosis.

Written by

Ernestas K.

Clinical research writer specializing in human health, biology, and preventive medicine.

Reviewed against ASH, NIH, Mayo Clinic, CDC guidelines · Last reviewed March 20, 2026