Many health problems can be detected through a urine test. Although the most common study in medical consultations is the so-called urinary sediment, there are other tests that provide a lot of information about a person’s general health. However, as with the results of blood tests, the data they provide are often difficult to understand by non-experts on the subject. This article describes what each of the determinations of a urine test means and how to interpret them .
Urine sediment: what information does it give?
Urine sediment provides very valuable information, not only of the kidneys and the excretory system, but of the whole organism and the general health of a person. Its name is because, for its realization and with the objective of separating the solid parts of the liquid, the sample is centrifuged. And what is analyzed is the resulting sediment or sediment . In this type of analysis, what is more important is the study of the cells present, such as leukocytes and red blood cells.
The presence of leukocytes , also called white blood cells, usually indicates urinary tract infection. When it is detected, the urine is cultured to isolate the microorganism and to perform an antibiogram to determine its sensitivity to antibiotics.
In normal urination , hematitis , or red blood cells, should be found . When more than five cells are detected per field, it is called hematuria. Its presence in the urine can be due to injuries of the urinary route (stones, infections or tumors), and this forces to an in depth study.
If there are microorganisms , it means that there is infection, although it is also easy to find them if the sample has not been collected in good hygienic conditions.
Other data that are detailed in a report of urinary sediment are:
- Glucose : its presence indicates elevated levels of blood glucose.
- Albumin : Under normal conditions, there are small amounts . Abnormal values should make you suspect kidney disease. Febrile states and intense exercise increase levels.
- Epithelial cells : they come from the bladder and urethra, and are normal.
- Cylinders : they are formed by mucoproteins that come from the renal tubules. The urine of a healthy individual includes less than five per microscopic field , which can be increased after intense activity.
- Crystals : normally contains crystals (uric acid, phosphates …). Their analysis can point to the composition of kidney stones in individuals with nephritic colic.
- Ketone bodies : can be observed in prolonged fasting and in states of decompensation in diabetic people.
- Density : ranges from 1.012 to 1.024 , depending on fluid intake.
- pH : Normal urine is slightly acidic. Small variations in pH may be induced by diet and certain medications .
There are substances that are eliminated through the urine that can interfere and give wrong results, such as some cough medicines
When it is necessary to study in a more complete way certain aspects of the functioning of the kidney , the analysis of urine collected during 24 hours is used. In order to take the sample correctly the first micturition should be discarded in the morning and then all the micturitions must be collected during the next 24 hours in a suitable container supplied by the health center or, if not, purchased at a pharmacy.
Increased values of creatinine , a protein of muscular origin that circulates in the blood and that is eliminated through the urine, usually indicate a malfunction. One of the most accurate tests to know the health of the kidneys is the comparison of the levels of creatinine in blood with which it contains the emitted emitted during 24 hours. This determination called creatinine clearance provides an estimate of the amount of blood that passes through tiny filters in the kidneys, called glomeruli, that is, glomerular filtration.
Since one of the primary functions of the kidney is the elimination of water and salts, the study of its activity is completed with the levels of sodium, potassium, chlorine and bicarbonate . The levels of calcium and phosphorus are also good indicators of the health of this body, as well as providing important information on bone metabolism.
The amount of protein present is also a good guide to know the progress of the kidney. They are not found in the urine, except in some circumstances such as during pregnancy or after sports . Keep in mind that their existence may be due to various causes, such as fever , inflammation or burns. If not, the proteins in the urine may indicate an alteration in normal functioning.
This study also allows to determine the levels of some hormones and their metabolites . Since many hormones have a different secretion depending on the time of day, measuring their levels for 24 hours gives a more accurate idea of the activity of the glands. The most frequently requested are those that measure the activity of the adrenal glands (cortisol, catecholamines, adrenal steroids …).
Medications and toxins in urine
The analysis of a urine sample is the best way to find toxins , psychoactive substances and some drugs in the body. It is used routinely in the emergency services and to discard doping of athletes. A rapid test is performed , where a positive result indicates the presence of the toxicant, but gives no idea of the amount. In case of doubt, or if levels are to be known, the results should be confirmed by other analytical techniques.
Occasionally, there are substances that are eliminated through the urine that can interfere and give erroneous results, as with some cough medicines or diarrhea, which may give false positives to heroin, due to their similar structure. On the other hand, a negative result does not exclude small amounts of the toxicant that are below the limits that the technique can detect.
In addition to some drugs, cocaine, cannabis , amphetamines and derivatives, barbiturates , benzodiazepines , methadone and opiates can also be found . In most cases, the poison remains in the urine for up to three days. If the substance is cannabis and consumption is sporadic, it is found within a week; and if usual, persists up to six weeks. Benzodiazepines can be detected up to 15 days later.