Can consuming 15 drinks/week cause an elevated Mean Corpuscular Volume (MCV)?

From the Guidelines

Consuming 15 drinks per week can cause an elevated Mean Corpuscular Volume (MCV) due to the direct effects of alcohol on red blood cell production and folate metabolism. This level of alcohol consumption is considered moderate to heavy drinking and can lead to larger-than-normal red blood cells (macrocytosis) [@\1@]. The Canadian stroke best practice recommendations suggest counseling individuals to follow Canada’s Low-Risk Alcohol Drinking Guidelines, which recommend no more than 15 drinks per week for men [@\1@]. However, it is essential to note that alcohol interferes with folate metabolism and directly damages bone marrow, impairing the normal maturation process of red blood cells. Some key points to consider include:

• The effect of alcohol on MCV is often dose-dependent, with higher alcohol consumption correlating with higher MCV values.
• Typically, an MCV above 100 fL (femtoliters) is considered elevated, and alcohol-induced macrocytosis may develop after several weeks to months of regular drinking at this level.
• This elevation can persist for 2-4 months after stopping alcohol consumption.
• If a patient presents with an unexplained elevated MCV, alcohol use should be considered as a potential cause, and reducing or eliminating alcohol intake would be recommended to normalize these values over time. Given the potential risks associated with elevated MCV and the direct impact of alcohol on red blood cell production, it is crucial to address alcohol consumption as a potential cause of elevated MCV.

From the Research

Relationship Between Alcohol Consumption and MCV

• Consuming 15 drinks/week may cause an elevated Mean Corpuscular Volume (MCV) as excessive alcohol consumption is known to elevate the MCV of erythrocytes 1.
• A study examining 105 alcoholics with a wide range of ethanol consumption found that the highest MCV occurred in the alcoholics, and moderate drinkers also showed a response to ethanol intake, with an upper normal limit for MCV of 98 fl 1.
• The relationship between ethanol consumption and MCV is dose-related, and chronic ethanol consumption may lead to changes in red blood indices 1.

Other Factors Affecting MCV

• Vitamin B12 deficiency can also cause an elevated MCV, and it is essential to monitor serum folate and cobalamin levels in patients with macrocytosis 2, 3.
• A systematic review found that the sensitivity of MCV for B12 deficiency was 17% in a randomly screened population, and 30% in patients with anaemia 3.
• Vitamin B12 deficiency can affect individuals at all ages, and diagnostic biomarkers include decreased levels of circulating total B12 and transcobalamin-bound B12, and abnormally increased levels of homocysteine and methylmalonic acid 4, 5.

Diagnostic Considerations

• An elevated MCV can be used to make the diagnosis of B12 deficiency more or less probable, but it should not be used as the only parameter to rule out the diagnosis of B12 deficiency 3.
• The MCV can be used to justify the measurement of serum B12, and a comprehensive diagnostic approach is necessary to determine the underlying cause of an elevated MCV 3, 4, 5.