What other names does it have?
Positive leukocyte esterase test +
ICD-10: R82.9
What is leukocyte esterase?
A positive (+) urine leukocyte esterase result indicates the presence of white blood cells in the urine.
Leukocyte esterase is an enzyme produced by white blood cells that contain granulocytes (those that have granules in the cytoplasm) such as neutrophils, basophils, and eosinophils. It is also secreted by monocytes. Lymphocytes are the only white blood cells that do not make this enzyme. Before a urinary infection, there is an increase in white blood cells in the urine, mainly neutrophils.
Therefore, the measurement of leukocyte esterase in the urine is an indirect measure of the presence of white blood cells or leukocytes in the urine without the need to study the urine sediment under a microscope.
It has the advantage that it can detect broken or intact white blood cells (lysates) and the disadvantage that it is not intended to determine the concentration of leukocytes in the urine since the quantification must be done by microscopic examination.
Esterases are also present if there are histiocytes or protozoa of the Trichomonas species (parasites that cause trichomoniasis).
What is the analysis done for?
The urine leukocyte esterase test is diagnostic useful when it is positive (+) because it usually indicates bacterial urinary tract infection or vaginal Trichomonas infections.
This test is usually performed in conjunction with the urine nitrite test as the two results together provide more information.
In women who suffer from dysuria (pain when urinating), if the leukocyte esterase and nitrites in the urine are both positive, it usually corresponds to a urinary tract infection with a very high probability (greater than 90%).
If the leukocyte esterase is positive and the nitrites negative, it points to a vaginal infection (trichomoniasis or chlamydia) or chronic interstitial nephritis.
In pregnant women, the leukocyte esterase test can be used to detect infections in the amniotic fluid.
How is the test performed?
The leukocyte esterase test is usually performed in conjunction with other routine urine analysis tests for which the patient must collect a small part of the urination in a jar or jar.
The urine collected must be a clean urine sample. It means that you must first urinate the first part in the toilet or urinal to later collect the urine in the bottle until a sufficient amount is completed and finally the rest is urinated in the toilet. It is important when collecting urine to avoid contamination by vaginal secretions.
For the leukocyte esterase test, test strips are used in contact with the collected urine. These strips usually change color after a certain time (approximately 2 minutes) in the presence of high values. If color changes occur after that time they are not relevant.
In laboratories, some machines carry out the procedure in an automated way, but test strips are also sold to perform urine tests at home.
What are normal urine leukocyte esterase values?
The urine leukocyte esterase test must be negative to be considered normal.
What does a positive urine leukocyte esterase result mean?
Urine leukocyte esterase results have diagnostic value when the result is positive (+).
The most common reasons for testing positive (+) for urine leukocyte esterase are:
Bacterial urinary tract infections (especially if nitrites in the urine are positive)
Cystitis
Urethritis
Prostatitis
Pyelonephritis
Non-bacterial vaginal infections (nitrites are usually negative)
Trichomoniasis
Chlamydia
Gonorrhea
Lithiasis
Chronic interstitial nephritis (normally negative nitrites)
Amniotic fluid infection in pregnant women
What substances can interfere with the results?
Some medications or circumstances can interfere with the results such as:
Ascorbic acid (vitamin C) in urine
High concentration of protein in the urine
Some antibiotics
Gentamicin
Cephalexin
# Now let’s find out the pH of urine?
What other names does it have?
urinary pH
acid urine
alkaline urine
ICD-10: R82.99
What is pH in urine?
Urine pH is a measure of how acidic or alkaline your urine is. PH is short for “Hydrogen potential” or “Hydrogen power” and is a value that depends on the concentration of hydrogen ions present.
If the pH is above 7 it is said that the urine is alkaline while if the pH of the urine is below 7 it is said that the urine is acidic.
The pH of the body and urine is regulated mainly by the functioning of the lungs and the exchange of ions in the renal tubules.
What is this analysis done for?
A healthy person usually has acidic urine (pH between 5.0 and 6.0) if the first urine sample is collected in the morning. If the urine sample is taken after a meal, slightly higher values are usually present.
Urine pH is often of diagnostic importance for the prevention of kidney stones. For this, the type of crystals that appear in the urine must be analyzed since certain crystals are more likely to form in the presence of acidic urine and others in the presence of alkaline urine.
Sometimes it is convenient that the urine is kept at a certain pH to avoid the formation of certain kidney stones, which is why the urine is forced to remain acidic or alkaline.
For example, in people who tend to form uric acid, cystine, or calcium oxalate crystals, it is advisable to maintain alkaline urine with a pH above 6.5 by administering medications (ammonium chloride, methionine, mandelic acid).
In other cases, it is advisable to keep the urine acidic to avoid the proliferation of bacteria which occurs in urinary tract infections or if the person is prone to forming calcium carbonate or phosphate kidney stones. These people can lower the pH of their urine by drinking cranberry juice frequently.
How is the sample taken?
The test to measure the pH in the urine is usually carried out in conjunction with other urine analysis tests for which the patient must collect a small part of the urination in a jar or jar. For the pH test, test strips are used in contact with the collected urine.
In laboratories, there are automated machines that carry out this process, but test strips are also sold to perform urine tests at home.
What pH values in urine are considered normal?
Urine pH values between 4.5 and 8 are considered normal.
The following ranges can be distinguished:
pH between 6.5 and 7.5: Neutral or balanced urine
pH between 6 and 6.5: Acidic urine
pH <5: Very acidic urine
pH> 7.5 Alkaline urine
Most often, the urine has values close to 6 so it is usually slightly acidic.
Very acidic urine
4.5 5 5.5 5.75
Acid urine
6 6.5
Neutral urine
6.75 7 7.25
Alkaline urine
7.5 8 8.5 9
Alkaline urine
If the pH values are above 7.5 it is said that the urine is alkaline. Alkaline urine can be due to:
Vegetarian diet or high consumption of citrus fruits or vegetables
Urinary tract infection by bacteria such as Proteus, pseudomonas, etc. (except Escherichia Coli)
Respiratory alkalosis (hyperventilation)
Vomiting
Renal tubular acidosis
Acid urine
If the pH values are below 6.5, the urine is said to be acidic. Acidic urine can be due to:
High protein diet with high consumption of meat and eggs
Cranberry juice
Metabolic acidosis
Respiratory acidosis
Diabetic cetoacidosis
Emphysema
Mellitus diabetes
Starvation
Dehydration
Severe diarrhea
Uremia
Escherichia Coli infection
What medications can interfere with the results?
Some medicines used to treat urinary tract infections such as mandelamine (methenamine mandelate) or fosfomycin trometamol can cause the urine to become acidic (pH <7).
Some treatments with sulfonamides or for kidney stones with sodium bicarbonate, potassium citrate, or acetazolamide can cause the urine to become alkaline (pH> 7)
