Tea & Fasting for a Blood Test

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People who normally drink tea in the morning may have to forego that pleasure when preparing for a diagnostic blood test. Many common blood tests require fasting to produce an accurate sample for evaluation. Your ability to follow instructions will determine how successful you will be.

Type of Blood Work

Fasting and nonfasting blood tests are often combined for convenience and for comprehensive health checks. Your doctor may order a single specimen drawn to evaluate a number of different aspects about your physical conditions, including organ function, nutrient levels, blood cell count and disease risk factors. Assessments such as lipoprotein profiles and glucose tolerance tests typically require fasting. Your health care provider will let you know when and how long to fast, and how fully you must meet the definition of fasting.

Your Daily Diet vs. a Fasting Diet

Fasting diets for blood work consist of water only, with no other beverage or food for a specified time. If you use an herbal tea to induce drowsiness before you go to bed at night, you will have to skip that aid if your blood test requires overnight fasting. Ask your doctor whether you can have sleep medication while fasting in case you need it. If you usually have a cup or more of tea, coffee or another beverage other than water with breakfast in the morning, you must alter that part of your diet on the day of the test. Black tea and coffee may change your blood chemistry and are not allowed while fasting.

How to Get Ready

A change in dietary routine is more difficult for some people than others. You can alleviate anxiety about fainting or missing your morning tea and breakfast on the day of your blood draw by packing a to-go snack the night before. Reduce the impact of fasting on your system by eating a healthy dinner before you start your fast and having plenty of cold water available.

How to Fast

Your doctor will tell you where your fasting needs fall in the average eight to 12 hours typically required and whether you are allowed to deviate from a water-only regimen. Unless otherwise instructed, do not add anything such as tea, coffee or lemon to the water that you drink. Do not eat any food until after you have given your blood specimen at the lab.