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Brain & nervous system
Vitamin B1 (thiamine) test
Thiamine status within a nutrient panel.
At a glance
In about 5 days
Most results are ready in about 5 days. Some specialty markers can take up to 21 days.
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What it measures
Shows your level of thiamine, also called vitamin B1. Thiamine helps your body turn food into energy and keeps your nerves and heart working well.
Why it matters for women
Severe, ongoing vomiting in pregnancy, called hyperemesis gravidarum, can use up thiamine quickly. Very low levels can affect the brain and nerves, so it’s something doctors watch for. Weight-loss surgery, heavy drinking and very restricted diets can also lower thiamine.
You might check it if…
- you’ve had severe, ongoing vomiting, including in pregnancy
- you’ve had weight-loss surgery
- you drink alcohol heavily
- you eat very little or follow a very restricted diet
What your result may mean
High Vitamin B1 (thiamine): what it may mean
High thiamine may mean you take a supplement, including B-complex vitamins or a multivitamin, and it may not be toxic in healthy people. Extra thiamine can leave the body in urine, so a high level can settle once intake changes. A recent thiamine shot or IV can raise it sharply, which may be expected after treatment for severe vomiting in pregnancy or after weight-loss surgery. A high level by itself may cause no symptoms.
Low Vitamin B1 (thiamine): what it may mean
Low thiamine (vitamin B1) may happen with long-term heavy drinking, malnutrition, severe vomiting in pregnancy (hyperemesis gravidarum), or after weight-loss surgery. Very low levels can cause Wernicke's encephalopathy, a brain emergency that can bring confusion, unsteady walking and eye movement problems. Some people may notice tiredness, irritability, poor appetite or numb feet. The body can store only a small amount, so levels can drop within weeks of poor intake. With severe vomiting, a clinician may act on symptoms before results come back.
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These notes provide context and do not diagnose a condition. Not yet available in NY, NJ, RI, HI, ND, SD or WV.