Understanding the ICD-10 Code for Vitamin K2 Deficiency and Its Nutritional Implications

October 18, 2025 •

4 min read

While severe vitamin K deficiency is rare in adults, it can have serious health implications, particularly for newborns and individuals with certain medical conditions. A specific ICD-10 code does not exist for K2 alone, but rather a deficiency falls under the general diagnosis for vitamin K deficiency, which medical professionals code as E56.1.

Quick Summary

This article explains that there is no separate ICD-10 code for vitamin K2 deficiency, and it is categorized under the broader code E56.1 for overall vitamin K deficiency. It covers the different types of vitamin K, K2's specific functions in bone and heart health, its symptoms, diagnostic methods, and rich food sources like fermented and animal products.

Key Points

ICD-10 Code: There is no specific ICD-10 code for vitamin K2 deficiency; it is categorized under E56.1 for general vitamin K deficiency.
K1 vs. K2: Vitamin K1 is primarily for blood clotting and comes from leafy greens, while K2 supports bone and heart health and is found in fermented and animal foods.
Bone Health: Vitamin K2 activates osteocalcin, a protein that binds calcium to bones, promoting density and strength.
Cardiovascular Health: K2 helps prevent arterial calcification by activating Matrix Gla Protein, which inhibits calcium deposition in blood vessels.
Deficiency Symptoms: Signs include easy bruising, excessive bleeding, blood in stool or urine, and decreased bone density.
Diagnosis: A vitamin K deficiency is diagnosed with a prothrombin time (PT) blood test, which measures how quickly blood clots.
Rich Food Sources: Excellent sources of vitamin K2 include natto, hard cheeses, egg yolks, liver, and other fermented foods.

Understanding Vitamin K: K1 vs. K2

Vitamin K is a fat-soluble vitamin essential for several bodily functions, including blood coagulation, bone health, and cardiovascular wellness. It is not a single compound but a group of structurally similar substances known as vitamers. The two main natural forms are vitamin K1 (phylloquinone) and vitamin K2 (menaquinone).

Vitamin K1 is predominantly found in plant-based foods, especially green leafy vegetables such as kale, spinach, and broccoli. It is primarily directed to the liver, where it plays a critical role in activating proteins necessary for blood clotting.

In contrast, vitamin K2 is found in animal products and fermented foods and is also produced by bacteria in the gut. Unlike K1, K2 is redistributed throughout the body, where it serves crucial extrahepatic functions, meaning outside the liver. This makes vitamin K2 particularly important for long-term bone and vascular health.

The Critical Functions of Vitamin K2

While K1 is vital for blood clotting, K2 is increasingly recognized for its distinct, far-reaching health benefits. Its longer absorption and activity time in the body allow it to perform unique tasks beyond the liver.

Bone Health and Calcium Metabolism

Vitamin K2 plays a central role in maintaining strong bones by activating a protein called osteocalcin. Activated osteocalcin, in conjunction with vitamin D, binds calcium to the bone matrix, ensuring proper mineralization and increasing bone density. A deficiency can impair this process, potentially increasing the risk of fractures and osteoporosis, especially in older adults. In some Asian countries, certain forms of vitamin K2 (MK-4) are even used to treat osteoporosis.

Cardiovascular Health

Perhaps one of the most exciting aspects of K2 research is its role in cardiovascular health. It activates Matrix Gla Protein (MGP), a potent inhibitor of soft-tissue calcification. MGP's activation prevents calcium from being deposited in arteries and other soft tissues, which can reduce the risk of arterial stiffness and the development of atherosclerotic plaque. Studies have correlated higher vitamin K2 intake, but not K1, with a reduced risk of coronary heart disease and other cardiovascular events.

Other Potential Benefits

Emerging research suggests vitamin K2 may have other health benefits, such as reducing inflammation, supporting brain function, and even possessing antioxidant properties. These potential benefits highlight the multifaceted importance of this often-overlooked nutrient.

What is the ICD-10 code for vitamin K2 deficiency?

Medical coding is crucial for diagnosis, billing, and research. However, there's no specific ICD-10 code dedicated solely to a vitamin K2 deficiency. Instead, both K1 and K2 deficiencies are reported under the same, broader code.

The ICD-10 code for vitamin K deficiency is E56.1.

This code covers all forms of vitamin K deficiency. When a healthcare provider documents this code, it indicates a general vitamin K deficiency based on laboratory findings and clinical signs. For newborns, a more specific code (P53) is used for hemorrhagic disease of the newborn. If the deficiency causes a specific coagulation factor problem, a code like D68.4 (Acquired coagulation factor deficiency) may be used in conjunction with E56.1.

Symptoms and Diagnosis

Symptoms of Vitamin K Deficiency

Since vitamin K deficiency is rare in healthy adults, symptoms often arise from underlying conditions causing malabsorption. Symptoms can include:

Easy bruising
Excessive bleeding from small wounds, injections, or surgical sites
Oozing from the nose or gums
Blood in the urine or stool (which may appear dark and tarry)
Heavy menstrual bleeding in women
Decreased bone mineral density (in long-term deficiency)
In infants, life-threatening intracranial hemorrhage or excessive bleeding after circumcision

Diagnosis

Diagnosis of a vitamin K deficiency begins with a physical exam and a review of symptoms. Blood tests are used to measure the efficiency of blood clotting. A common test is the prothrombin time (PT) test, which measures how long it takes for a blood sample to clot. A prolonged PT can indicate a vitamin K deficiency. A definitive diagnosis may involve administering a vitamin K supplement and observing if symptoms improve.

Nutritional Strategies for Optimal Vitamin K2

To prevent a deficiency and reap the extrahepatic benefits of vitamin K2, it's important to consume a diet rich in both K1 and K2. While K1 is easy to obtain from leafy greens, K2 is less common in a Western diet.

Some of the best food sources of vitamin K2 include:

Natto (a traditional Japanese fermented soybean dish, very high in MK-7)
Hard and soft cheeses (such as Gouda, Brie, and Münster)
Egg yolks
Goose liver and other organ meats
Certain dairy products (especially full-fat and fermented options)
Sauerkraut
Chicken

For those who may not consume enough K2 through diet, supplements containing MK-7 are often recommended due to their high bioavailability and longer half-life compared to K1.

Comparison Table: Vitamin K1 vs. K2


Feature	Vitamin K1 (Phylloquinone)	Vitamin K2 (Menaquinones)
Primary Source	Plant-based foods (leafy greens)	Animal products and fermented foods
Body Location	Primarily concentrated in the liver	Redistributed to extra-hepatic tissues (bone, blood vessels)
Primary Function	Activates liver proteins for blood clotting	Activates proteins for bone and cardiovascular health
Circulation Time	Short half-life, filtered quickly	Longer half-life, stays in circulation longer
Bioavailability	Relatively low absorption rate from plant sources	High absorption rate, especially MK-7
Known Subtypes	Single form	Multiple subtypes (e.g., MK-4, MK-7)

Conclusion: Integrating Vitamin K2 into Your Nutrition Diet

The ICD-10 code for vitamin K2 deficiency doesn't exist independently, but its diagnosis falls under the broader E56.1 for vitamin K deficiency. Understanding the differences between vitamin K1 and K2, particularly K2's vital roles in bone and cardiovascular health, is essential for a complete nutritional diet. While severe deficiency is rare, ensuring adequate intake through diet, especially fermented foods and animal products, can optimize your body's long-term health. If you suspect a deficiency, a doctor can perform a simple blood test to diagnose the issue and recommend a proper course of action, which may include dietary changes or supplementation.

Learn more about Vitamin K2 functions and benefits on Healthline.

Frequently Asked Questions

No, there is no specific ICD-10 code exclusively for vitamin K2 deficiency. The condition is reported under the broader code E56.1, which designates a deficiency of vitamin K generally.

Vitamin K2's primary functions are outside the liver, including activating proteins like osteocalcin for bone mineralization and Matrix Gla Protein (MGP) to prevent calcium accumulation in arteries.

The main symptom is excessive bleeding, which can manifest as easy bruising, nosebleeds, bleeding from the gums, and in severe cases, internal bleeding. For newborns, this is particularly dangerous and can lead to intracranial hemorrhage.

The best dietary sources of vitamin K2 are fermented foods and animal products, such as natto (fermented soybeans), hard cheeses, egg yolks, liver, and certain meats like chicken.

A doctor diagnoses a vitamin K deficiency by observing symptoms and performing a prothrombin time (PT) blood test, which measures how quickly your blood clots. A prolonged clotting time indicates a possible deficiency.

Leafy green vegetables are primarily a source of vitamin K1. While bacteria in the gut can convert some K1 to K2, the most reliable food sources of K2 are fermented and animal products.

Yes, supplements, particularly those containing the MK-7 form of vitamin K2, are considered effective for increasing serum levels of K2 and supporting bone and heart health, especially for those with low dietary intake.