1.What is fasting blood draw?
Fasting blood draw does not mean not eating the night before the blood draw, but should maintain the usual habits of life, normal light diet, no alcohol, no coffee and strong tea, good rest, no breakfast in the morning of the blood draw, little or no water, no morning exercise, calmly waiting for blood collection at the hospital. Pay attention to the time of dinner should not be too late, generally the end of dinner and the next morning blood collection time should be more than 8 hours apart. For patients suffering from chronic diseases such as hypertension, asthma and heart disease, taking medication with a small amount of plain water has little effect on the test, but sugary drinks and dairy products should not be consumed. If the patient’s triglycerides are particularly high, it may affect the accuracy of other blood lipid tests and require a vegetarian diet for several days before doing fasting blood tests.
2.What are the items that require fasting blood test and why?
(1) Blood glucose and glycated serum protein
The former refers to the blood glucose content measured between 6:00 am and 8:00 am after fasting for 8-12 hours from the previous day’s dinner to the next morning, and the “super fasting” blood glucose after 10:00 am will affect the test results. Glycated serum protein can reflect the average blood glucose level in the past 4 weeks, and its result is positively correlated with blood glucose concentration.
(2) Blood lipids
Blood lipid level is closely related to eating, and it is significantly higher after meal than before meal, so fasting blood must be checked.
(3) Liver function
Reflecting liver metabolism, such as ALT, AST, total bile acids and ¡-GT, and reflecting protein metabolism, such as total protein (TPO), albumin (ALB) and globulin (GLO) are affected by diet, so fasting is required.
(4) Kidney function (including uric acid)
Urea nitrogen (BUN), creatinine (Cr) and uric acid (UA) are greatly affected by diet and exercise and need to be fasted.
(5) Blood electrolytes
Including potassium (K), sodium (Na), chloride (C1), calcium (ca), magnesium (Mg) and phosphorus (P), etc. Eating will affect the results.
(6) Immunoglobulin, rheumatoid factor, anti-“O” and C-reactive protein
At present, most hospitals use turbidimetric method for testing, because the instrument is not specific for turbidity identification, in order to prevent the serum specimen on its influence, require fasting blood.
In addition to the above items, other items are not strictly required to fasting test, but from the accuracy and reference significance, it is best to fasting is better.
3.Can I take drugs for blood sampling on an empty stomach?
Generally speaking, employees do not need to stop taking medication before routine physical examinations, especially for patients with chronic underlying diseases, it is best not to stop taking medication without permission, otherwise serious consequences may occur. Such as diabetic patients to check fasting blood glucose before you can not take glucose-lowering drugs, fasting blood draw first before taking drugs, while hypertensive patients should take antihypertensive drugs before the physical examination.
4. Prevention and control of symptoms related to blood draws
In general, blood sampling will not aggravate the disease and affect the health, unnecessary concerns and fears.
In rare cases, the following may occur and can be resolved with appropriate treatment.
(1) Dizziness
It may be due to excessive weakness or nervousness of the patient or dizziness of the needle. In mild cases, pale face, weakness, dizziness, nausea, sweating, etc. Let the patient rest quietly and flatly or give some warm tea or sugar water. Usually after rest, the patient’s symptoms will disappear. In case of serious illness, send the patient to the emergency room for treatment in a timely manner.
(2) Subcutaneous bleeding from hematoma
Usually due to improper pressure to stop bleeding, if there is no underlying disease, it can gradually disappear after a few days.
(3) Infection
Infection, redness and swelling can sometimes occur if care is not taken to protect the cleanliness of the needling site.