Common specimens for clinical tests generally include blood (referred to as blood, venous blood), urine, feces, cerebrospinal fluid, pleural effusion, prostatic fluid, semen, vaginal secretions, etc. The time, method and preservation of these specimens have certain requirements.

First, blood specimens

Some physiological factors, such as smoking, eating, exercise, mood swings, pregnancy, body position, etc., can affect changes in certain components of the blood, and some even have day and night changes. Therefore, the collection of blood specimens should avoid physiological factors as much as possible, and it is advisable to agree on conditions. If it is unavoidable, the factor should be indicated on the specimen.

1. Peripheral blood

Generally, the inner side of the ring finger of the left hand is selected for blood collection, and the site should be free of frostbite, inflammation, edema, and damage. If the part does not meet the requirements, replace it with other finger parts. For burn patients, blood can be collected from the intact skin. Because some blood routine tests (such as white blood cell count, classification, etc.) are subject to excessive fluctuations due to physiological factors, the conditions should be as uniform as possible. For the detection of in vivo and coagulation tests (such as platelet count, bleeding time or clotting time), it is important to pay attention to whether the patient has used anticoagulant or procoagulant drugs in order to reduce or avoid the influence of interference factors.

2. Venous blood

In addition to anti-coagulation venous blood plasma, which is involved in various hemostasis and thrombus testing projects, most of the current testing items can be directly used for venous blood serum. In the serum testing program, some (such as blood sugar, blood lipids, etc.) are greatly affected by diet and day and night factors, generally in the early morning fasting blood specimens; some in the blood decay faster (serum enzyme activity such as ACP activity, etc.), The storage activity of 0~4°C is weakened. The detection of these items must be timely and rapid; some (such as creatine kinase) are greatly affected by factors such as exercise. It is also important to avoid the occurrence of hemolysis during blood draw, especially in the determination of serum potassium, LDH, etc.

Second, urine specimens

Like blood samples, urine specimens are also affected by factors such as diet, exercise, and drug dosage, especially the effects of diet, so morning urine is generally better than random urine. Morning urine refers to the first urine specimen after getting up in the morning. It is concentrated and acidified, and the formation points (such as blood cells, epithelial cells, and tubular shape) are relatively concentrated for easy observation. Random urine is a random urine, easy to stay, but is more affected by diet, exercise, drugs, prone to false positive and false negative results, such as dietary proteinuria, dietary diabetes, vitamin C interference occult blood results. Postprandial urine (patient urine collected 2 hours after lunch) is suitable for urine sugar, urine protein and urobilinogen examination. At this time, urine specimens can increase the sensitivity of the test and detect milder lesions. The 12-hour urinary cell count, which is the Addis count (all urine collected after emptying the bladder at 8 pm to 8:00 am the next day), is prone to multiplication due to the long time, and the preservative formaldehyde must be added. Quantification of chemical substances in 24-hour urine (all urine collected after emptying the bladder at 8 am on the first day to 8:00 am the next day), including protein, sugar, urinary 17-ketone, 17-hydroxysteroid, catecholamine, Ca2+, etc., detect different substances and choose different preservatives for preservation. Clean mid-stage urine is mostly used for urinary bacterial culture. It requires sterility and samples are taken after rinsing the vulva. All urine specimens should be collected in a sufficient amount, at least 12 ml, preferably 50 ml. All urine must be collected at regular intervals. For female patients, vaginal secretions and blood-contaminated urine specimens should be avoided.

Third, stool specimens

The detection of stool specimens has important reference value for judging diseases of the digestive system. At the time of collection, it is required to use a clean bamboo stick to select feces containing abnormal components such as mucus and pus, and the feces without abnormal appearance must be taken from the surface, deep and feces. The count of parasites and eggs should be collected for 24 hours of feces. Check the dysentery amoeba trophozoite should be checked immediately after defecation, from the pus and soft place, heat preservation for inspection. When examining the eggs of Schistosoma japonicum, the mucus and pus and blood should be taken. At least 30 g of feces should be taken when hatching the mites, and it should be treated as soon as possible. Check the mites eggs with a clear film swab and swab from the wrinkles around the anus at 12 pm or early morning defecation and immediately microscopically. The occult blood test (chemical method), fasting meat and animal blood foods on the 3rd day before the test and banned iron, vitamin C and so on. All fecal specimens should be inspected within 1 hour of collection to prevent damage to the formed enzymes and pH.

Fourth, cerebrospinal fluid specimens

The cerebrospinal fluid specimens are sent for inspection immediately after collection. If they are placed for too long, the test results will be affected: if the cells are denatured and destroyed, the counting and classification will be inaccurate; some chemical substances such as glucose will reduce the decomposition content; the bacteria will be autolyzed to affect the detection rate of bacteria. . After the cerebrospinal fluid is extracted, three sterile tubes are generally divided. The first tube is used for bacterial culture, the second tube is used for chemical analysis and immunological examination, and the third tube is used for general traits and microscopic examination. The order of the three tubes should not be reversed. Due to the difficulty in collecting specimens, all inspection and testing procedures should be safe.

Five, chest and ascites specimens

As with the cerebrospinal fluid specimens, the collected specimens are safe and promptly sent for inspection. Generally, three tubes are also dispensed, one tube for routine cytological examination, one tube for biochemical examination, and one tube for bacterial culture, and the order is the same as cerebrospinal fluid.

Six, prostate fluid specimens

The specimen of prostatic fluid is collected from the prostate after massage. When the amount of fluid is small, it is directly dripped on the slide and sent for inspection. It is necessary to prevent the specimen from being evaporated and dried. When the amount is large, it is collected in a clean and dry test tube. If the prostatic fluid is not massaged, the urine sediment after the massage can be checked.

Seven, semen specimens

Semen specimens should be forbidden for 3 to 7 days before collection. After the urine is drained, the semen can be directly discharged into a clean container by masturbation or other methods, and kept warm and promptly sent for inspection. Due to the large variation of sperm production during the day, it should be checked 2~3 times (1~2 weeks apart) for diagnosis.

Eight, vaginal secretions specimens

The vaginal specimens should be banned from sexual intercourse, bathing, vaginal examination, vaginal lavage and topical medicine 24 hours before collection. The equipment used for the preparation should be cleaned. Generally, a cotton swab soaked with salt water is taken from the deep part of the vagina or the posterior part of the vagina, the cervical canal, etc., and the vaginal secretion specimen is observed after the saline smear, and the female patient of the menstrual period should not check the vaginal secretion specimen.

Please download the file for more content...