From the Guidelines
A serum B12 level of 233 pg/mL is considered below the normal range, according to the ESPEN micronutrient guideline published in 2022 in the journal Clinical Nutrition 1. This guideline defines adequate status as blood/plasma concentrations within the local reference range, and a level of 233 is likely below this range.
- Normal B12 levels typically range from 250-900 pg/mL, though some labs may have slightly different reference ranges.
- With a level of 233, it is recommended to consult with a healthcare provider as supplementation may be beneficial.
- Options for supplementation include oral vitamin B12 supplements, B12 injections, or increasing B12-rich foods in the diet.
- Additional testing, such as methylmalonic acid (MMA) and homocysteine levels, may be recommended to assess functional B12 status.
- Addressing B12 deficiency is crucial, as it can lead to fatigue, neurological symptoms, and anemia over time, highlighting the importance of monitoring and treating borderline deficiency cases, as suggested by the ESPEN guideline 1.
From the Research
Serum B12 Levels
- The normal range for serum B12 levels can vary depending on the laboratory and the specific test used 2.
- A study published in 2021 found that a serum vitamin B12 level below 250 pg/mL was considered deficient 2.
- Another study published in 2016 defined vitamin B12 deficiency as a serum vitamin B12 level <200 pg/mL 3.
- A serum B12 level of 233 pg/mL is likely to be considered within the normal range, although this may depend on the specific laboratory and test used.
Comparison to Deficiency Thresholds
- A study published in 2021 found that patients with serum vitamin B12 levels below 250 pg/mL were considered deficient and were treated with vitamin B12 supplementation 2.
- Another study published in 2016 found that patients with serum vitamin B12 levels <200 pg/mL were considered deficient 3.
- In comparison, a serum B12 level of 233 pg/mL is above the threshold of 200 pg/mL, but below the threshold of 250 pg/mL used in some studies.
- It is worth noting that the normal range for serum B12 levels can vary depending on the laboratory and the specific test used, and some studies may use different thresholds to define deficiency 4, 5, 6.
Clinical Significance
- Vitamin B12 deficiency can cause a range of clinical symptoms, including fatigue, neurological symptoms, and macrocytic anemia 2, 3.
- A serum B12 level of 233 pg/mL may not be considered deficient, but it is still important to consider the clinical context and other laboratory results when interpreting this value.
- Further evaluation and testing may be necessary to determine the clinical significance of a serum B12 level of 233 pg/mL and to rule out other potential causes of symptoms 2, 3.