Specimen Requirements

Alternate Specimen Requirements

Minimum Specimen Requirements

Stability

Days Performed

Sun - Sat

Turnaround Time

8 hours

Methodology

Special Info

A fasting sample is preferred but not required. Patients taking a biotin dose of up to 5 mg/day should refrain from taking biotin for 4 hours prior to sample collection. Patients taking a biotin dose of 5 to 10 mg/day should refrain from taking biotin for 8 hours prior to sample collection. Patients taking a biotin dose > 10 mg/day should consult with their physician or the laboratory prior to having a sample taken. Clinicians should consider biotin interference as a source of error, when clinically suspicious of the laboratory result.

Clinical Info

Vitamin B12 (cobalamin) is important for maintaining metabolism, brain and nervous system functions, and the formation of red blood cells. Vitamin B12 is not produced by the human body, so it must be obtained through eating animal proteins such as meat, dairy, or eggs. Although the body can store sufficient vitamin B12 reserves for 2 to 5 years, deficiency can develop due to extended nutritional insufficiency among strict vegetarians, vegans, or elderly patients with limited diets. Vitamin B12 deficiency is also caused by malabsorption issues such as pernicious anemia or underlying disorders or damage to the stomach, small bowel, or pancreas. Testing for vitamin B12 is performed to detect deficiency and monitor vitamin B12 therapy. Symptoms of vitamin B12 deficiency include macrocytic megaloblastic anemia, peripheral neuropathy, glossitis, hyperreflexia, ataxia, poor coordination, deficient proprioception, affective behavioral disorder, weakness, and fatigue. Some patients may show the neurological or psychiatric defects without anemia, particularly the elderly.