What affects lab results

Patients: When you go to the hospital, the doctor often needs to take blood tests, or urine or stool tests according to your condition. You know what? In order to make your test results can truly reflect your physical health, in addition to the technical level of medical personnel and medical equipment should be in the best condition, some of your own factors will also have a certain degree of impact on your test results. General requirements: generally need to collect blood in a quiet state, patients should avoid strenuous exercise and alcohol consumption before blood collection, should not change diet and sleep habits, outpatients advocate sitting still for 15 minutes before blood collection The effects of exercise Fatigue will make the blood glucose, creatine kinase, aspartate aminotransferase, lactate dehydrogenase and so on increased; prolonged exercise will make the leukocytes, urea, creatine, lactate, bicarbonate ions unstable; nervousness, emotional excitement may affect the nerves, and may also affect the blood of the patient. ; tension and emotional excitement may affect neuroendocrine function and respiration, resulting in elevated lactate. Therefore, blood specimens should be taken when the patient is quiet and emotionally stable; do not do strenuous exercise the night before blood collection. Do not take a long walk in the morning on the day of blood collection, and rest for at least 10 minutes before blood collection. Plasma fat, protein and sugar are elevated after meals, and celiac blood may appear. Blood collection is most stable 8~12 hours after meal, blood sugar, phosphorus, calcium, uric acid are changed after meal, such as a standard meal after glyburide triacetin, blood sugar can increase 50%, aspartate transferase increase 20%, bilirubin, inorganic phosphorus, calcium, Na and cholesterol increase about 5%; but fasting for more than 16 hours, the same will also affect the composition of the blood. For example, serum albumin, complement, transferrin and glucose decrease. If fasting for 48 hours, serum bilirubin increases, so fasting time is not the longer the better. The effect of drinking alcohol After drinking alcohol, lactic acid, uric acid, etc. are affected, long-term alcohol consumption will cause high-density lipoprotein, cholesterol, etc. to rise. The effect of smoking After smoking, the ratio of blood carboxyhemoglobin can reach 8%, which is 1% for normal people. Prolonged smoking can also cause a mild increase in the concentration of carcinoembryonic antigen. Selection of blood collection time: Generally, patients are required to fast for 12 hours before blood collection, and the time of blood collection is more appropriate at 7~9 am. After meal and prolonged fasting time (starvation) will affect the chemical composition of blood, therefore, from the scientific point of view, the time of blood collection should not be prolonged. Blood collection should be scheduled as close as possible to the time of examination and treatment. The collection time must take into account the patient's biological clock pattern, especially hormone levels. For example, reproductive hormones are closely related to the menstrual cycle, cholesterol is highest at this time and lowest at ovulation. Calcium is at its lowest at midday. Therefore, blood collection should be done at the same time. Patients doing glucose tolerance test or two-hour postprandial glucose must know in detail when to take glucose, record the time and plan when to collect blood. Choice of blood collection method Influence of patient's position: Blood should be taken relatively stationary, sitting or lying down, and patients should be given 10 minutes to stabilize their position before blood collection. The position of the patient affects the circulation of the blood, in which the changes in macromolecules and cellular components are more pronounced, so that the results of inpatients and outpatients will be different. Other influencing factors The influence of certain diagnostic and therapeutic means: for example, when blood is drawn to check the total prostate antigen in the serum, blood should be drawn first, and then do the relevant tests, otherwise, the accuracy of the test results may be affected. Drugs: the effect of drugs on the test is quite complex, 15,000 kinds of drugs have an interfering effect on the test. For example, chlorpromazine affects cholesterol; vitamin C affects blood sugar and cholesterol. Therefore, it is best to stop medication two days before blood collection, but must not affect the condition of the situation, certain hypoglycemic drugs, antihypertensive drugs should consult a doctor to avoid serious consequences. Factors affecting the results of urine examination: urine examination to retain the morning urine on the day of the good one is that morning urine is more concentrated, easy to detect the formation of components; the second is that each time to retain a fixed period of time, the conditions are constant, easy to compare. Unless the emergency, can be retained at any time to check the urine, ordinary urine test to the morning urine is better. Mid-range urine should be retained in a clean disposable container, and timely delivery. Leaving it for too long will affect the results. You should avoid mixing menstrual blood, tapes, semen, etc. into the urine, which will affect the results. Certain drugs, such as anti-tuberculosis drugs (isoniazid, rifampicin, etc.), hypoglycemic drugs, penicillin, vitamin C, etc., affect the results of urine tests. Factors affecting the results of fecal test: should avoid collecting urine pots, stool specimens in the urinal, so as not to affect the results: should be collected stool specimens in dry, non-absorbent clean containers, and timely delivery of the test, so as not to be placed for too long to avoid destroying the formation of points. Blood draw precautions 1, the day before the blood draw, it is best to take a bath or wash both arms, so that when the blood draw, disinfection will be better, to avoid wound infection. 2, the day of the blood draw, do not wear cuffs are too small and tight clothes, to avoid the blood draw, the sleeve can not be rolled up or after the blood draw, the sleeve is too tight, caused by the arm vasculitis.