There are many doubts about what the urinary sediment values are and about what reflects an alteration in them—microscopic urine sediment from urine examination after centrifugation of urine to observe sedimenting elements.
A study of the urinary sediment well done does not raise doubts about the result for the doctor; it indeed represents a procedure to make a diagnosis in a valuable and straightforward way by studying the solid elements of the urine; in FastlyHealwe will explain to you what it represents the changes in the urinary sediment and what are the average values, as well as the diseases that are associated with their alterations.
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Urinary sediment: a diagnostic method
The study of the urinary sediment is a relatively simple diagnostic method to carry out, which is highly valuable for the diagnosis. With this test, a microscopic assessment of the urinary sediment is made that allows to recognize of all the solid structures that the urine has: cells, cylinders, and crystals; all this is capable of providing essential data when pathologies such as urinary infections or asymptomatic bacteriuria are present.
This study is carried out by centrifuging the urine for approximately 7 minutes, observing the cells in detail through the microscope, and staining if necessary to facilitate the recognition of some urinary elements.
To assess the severity of the presence of nephropathies, the doctor must request the study of urinary sediment, where cells such as erythrocytes and leukocytes can be identified, as well as hyaline, granular and erythrocytic casts and finally, crystals such as uric acid and some drugs.
Urinary sediment: reference values
The formed elements are the bodies in suspension, that is, the solid part found in the urine and remains at the bottom after centrifugation, whose values will be essential for the doctor to determine if there is any pathology that has altered them or not. :
Its average value ranges from 1005 to 1035 depending on the laboratory and is also directly proportional to fluid intake; that is, a urinary density value close to the lowest value (relative to 1005) allows interpreting that the urine is diluted, and a value above or close to the high reference value (above 1035) indicates that the urine is concentrated, this is related to urine with an ammonia odor, this implies that we are in the presence of dehydration.
The urine is usually acidic, approximately between 5.5 and 7.0, which can vary from time to time due to diet or after taking some drugs. However, when, for example, the result is below 5.5, this translates into the presence of some renal tubular pathology or that there is blood acidosis; the opposite to this occurs when the urinary pH is above 7, 0 indicating to the doctor the presence of bacteria or the presumption of a high intake of vegetables and citrus fruits. Finally, this value may be related to the administration of sodium bicarbonate as a treatment for lithiasis.
The normality is that there is no evidence of glucose in the urine; what happens is that in the presence of high glucose in the blood, it ends up being filtered by the kidneys to be eliminated. A urine glucose test is positive when the patient suffers from diabetes mellitus; otherwise, when this pathology is ruled out, it is likely to be renal tubule disease.
Usually, proteins in urine must be absent; their size is huge to be filtered by the kidney, few of them manage to pass this barrier, but their value is so minimal that they are not usually detected; if the result is positive, it will be related to the concentration of protein in urine and reflected in crosses (+) protein traces (between 10 – 30 mg / dL), 1+ (30 mg / dL), 2+ (40 – 100 mg / dL), 3+ (150 – 350 mg / dL) and 4+ (> 500 mg / dL) these values indicate kidney failure.
Also known as red blood cells, their average value is described in 2 ways, the first of which is considered within the limits when it is between approximately 0 to 2 red blood cells per field or less than 10,000 cells per mL of urine. A minimal amount of erythrocytes is regularly eliminated in the urine; the morphological study of these red blood cells may indicate the origin of kidney disease.
In general, red blood cells are cells large enough that they make it difficult to pass through the filter that runs in the kidneys. When there is damage at this level, especially in the renal glomeruli, the presence of red blood cells (a high number above their average values) is reflected in the urinary sediment.
When the average value of erythrocytes is increased above two red blood cells per field, it is said that we are in the presence of hematuria. In the following article, we will talk about red blood cells high in the urine.
They are also known as myocytes, whose average values range below five leukocytes per field or less than 10,000 cells per mL of urine. These cells at above-average values indicate an inflammatory process in the kidney and urinary tract that must be studied and treated.
In some cases, it is difficult to make a differential diagnosis of urinary infection because, in the case of women, leukocytes from the vagina are regular, which undergo numerous changes during the month and in which various factors interfere.
(Squamous, transitional or renal, their average values range between 3 to 5 cells per field. These only have medical significance exclusively when they are found in large quantities and are also associated with the presence of leukocytes and red blood cells. These cells can come from anywhere in the urinary tract and are consequences of cell transformation and desquamation.
Usually, the cylinders should be negative or absent, or the hyaline cylinders present in a range of 2 – 3 per field. This group includes, in addition to hyaline casts, granular casts, erythrocytes, and finally, waxy casts. Their medical importance lies in the fact that they allow the diagnosis of kidney diseases and the prognosis; all models are pathological except the hyaline ones.
In most cases where the presence of cylinders appears in urinary sediment, it almost always reflects that there is kidney disease, except for hyaline that may be present in healthy people who perform physical exertion of great intensity and in the presence of dehydration.
There is a great variety of crystals in the urinary sediment, and it is also a common finding. Usually, the crystals must be harmful in the urinary sediment; of all of them, the one with the most clinical significance is uric acid, which is frequently found in pathologies such as gout and leukemia; ammonia-magnesium phosphate that is associated with urinary infections and hippuric acid is extremely rare but can appear in liver disease.
Its identification will be dependent on urinary pH; if we are in the presence of an acid pH, there will be uric acid, calcium oxalate, hippuric acid, and amorphous urates; on the contrary, in case of the presence of an alkaline pH, there will be amorphous phosphates, calcium phosphate, ammonia-magnesium phosphate, calcium carbonate, and ammonia urate.
Urinary sediment: other reference values
In addition, other elements that we can find in urinary sediment and that can help us when diagnosing disease are:
- Ketone bodies: from fat metabolism, its average value is negative or <20mg / dL; if positive, it is in decompensated diabetes mellitus or prolonged fasting.
- Bilirubin and urobilinogen: bilirubin is only detected in urinalysis when its blood values exceed 1.5 mg / dL., that is, when there is biliary obstruction. Otherwise, its average discount is negative; in the case of urobilinogen, its normal value is between 0.2 – 1.0 mg / dL; this has no clinical relevance in most cases except when its values are affected indicating the presence of liver pathologies, urobilinogen is a product of the metabolism of bacteria in the intestine.
- Nitrites: the normality is that the result is negative; in case it is positive, it indicates to the doctor or specialist the presence of bacteria; it is most likely to carry out a urine culture so that the diagnosis is much more precise; this is given to the possibility of false negatives.
- Albumin: its average value is the presence of small amounts of albumin in urine; if the value is abnormal, it reflects kidney diseases.
- Bacteria, fungi, and mucus: in a usual way, the bacteria must be harmful. Otherwise, you can be in the presence of urinary tract infection; fungi are expected to get if the patient suffers from diabetes mellitus. Finally, the mucus is present in small quantities, except when we are in the presence of irritation or inflammation of the urinary tract.
Recommendations for a good study of urinary sediment
Despite being a simple, reliable, and effective routine study, very few doctors tend to explain the correct way to take the sample, thus avoiding results that raise doubts at the time of diagnosis:
- Urine should be collected in a clean and dry sterile disposable container with a minimum capacity of 50 ml.
- The first urine in the morning is the ideal one to take the sample, this allows it to be more concentrated and the formed elements to be detected in a better way.
- Prior hygiene of the genital area is recommended.
- The sample to be taken is from the second urine stream; the first must be eliminated.
- If women are menstruating, it is not recommended to take the sample.
- Once the sample has been taken, it must be analyzed within 2 hours after collection. Otherwise, a temperature must be kept between 2 and 8 ° C to be able to study the urinary sediment.
Studying the urinary sediment is extremely easy if the appropriate measures are taken; the doctor requests the study to determine any alteration in the urinary tract. Any symptoms related to this issue should be consulted immediately with the specialist.
This article is merely informative, at FastlyHeal .com we do not have the power to prescribe medical treatments or make any type of diagnosis. We invite you to see a doctor in the case of presenting any type of condition or discomfort.
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I am a Surgeon with a diploma in comprehensive ultrasound and surgical care residency, an area I am specializing in. During the exercise of my profession, I have realized the need for patients to know the diseases they suffer, and I can tell you that a large part of their complications is due to a lack of information. Being a health web writer allows me to transmit my experience, without borders, to all those readers eager for knowledge, educate them in the prevention of diseases and promote a healthy lifestyle.