Urinalysis – Lab Care

About the test

Urine analysis is a frequent and important test, performed during a routine check-up, for diagnostic purposes, during pregnancy as well as pre-operatively.

It is used for screening of urinary tract infections, kidney and liver issues as well as diabetes.

Urinalysis typically includes the following stages:

1: Sample inspection

2: Chemical dipstick test

3: Microscopic examination

1. Sample inspection

During this stage the healthcare provider evaluates the following aspects:

Color
Appearance
Odor

2^.. Chemical dipstick test

The dipstick test uses a chemical strip that is submerged in the sample and changes color when exposed to different substances. A dipstick test may be used to check various aspects of the urine sample including:

Specific gravity
pH
Leukocyte esterase
Nitrites
Protein
Glucose
Ketones
Urobilinogen
Bilirubin
Hemoglobin

3. Microscopic examination

After the sample is centrifuged, the sediment is examined microscopically for:

White blood cells
Red blood cells
Bacteria
Casts
Crystals
Mucous
Lipid droplets

Sample

The first morning urine specimen is preferred.

Preparation

Before urination washing of the external genitalia with water and soap is required (Antiseptic soaps should be avoided). Rinsing of the area with abundant water and drying with a clean towel should follow.

Procedure

The urine sample should be midstream and collected in a special, sterilized container. It should be then transferred to the laboratory within an hour. If this is not possible the sample may be maintained in the fridge for up to four hours.

Toddlers: The sample is collected in special containers which look like small plastic bags.

Individuals with a permanent catheter: The area is disinfected and the sample is collected from the ureteral tube.

Evaluation of results and indicative pathologic findings

Test parameter	Normal values	Possible meanings of abnormal values

Physical characteristics
Color	Clear	Hematuria Jaundice
Appearance	Light yellow to amber	Urine infection Nephrolithiasis Hematuria Drugs Food
Odor	Distinct, usually mild	Urine infection Phenylketonuria Drugs Food

Chemical characteristics
Specific gravity	1005-1025	Elevation: Dehydration Acute glomerulonephritis Diabetes mellitus Reduction: Increased fluid intake Diuretics Diabetes insipidus Chronic pyelonephritis
pH	5-7	Elevation (alkaline pH): Bacteriuria Chronic renal failure Fanconi’s syndrome Metabolic alkalosis Urine infection Starvation Reduction (acidic pH): Dehydration Diabetes mellitus Metabolic acidosis Phenylketonuria Urine infection Renal tuberculosis
Leukocyte esterase	Negative	Urine infection Sample contamination with vaginal secretions
Nitrites	Negative	Urine infection
Protein	Negative	Diabetes mellitus Malignant hypertension Glomerulonephritis Multiple myeloma Pyelonephritis Systemic lupus erythematosus High protein diet Drugs
Glucose	Negative	Diabetes mellitus Gestational diabetes Cushing’s syndrome Fanconi’s syndrome Multiple myeloma Pheochromocytoma Stress Drugs
Ketones	Negative	Alcoholism Anorexia Diabetes mellitus Diarrhea Fasting Fever Hyperthyroidism Pregnancy Starvation Vomiting Drugs
Urobilinogen	Negative <0.1	Elevation: Acute hepatitis Liver cirrhosis Cholangitis Hemolytic anemia Serious infection Ecchymoses Reduction Renal failure Diarrhea Biliary obstruction
Bilirubin	Negative	Obstructive jaundice Hepatitis Liver cirrhosis Drugs
Hemoglobin	Negative	Acute tubular necrosis Benign prostate hypertrophy Hemorrhagic cystitis Pyelonephritis Urine infection Glomerulonephritis Drugs
Microscopic characteristics
White blood cells	0-2 per optical field	Urine infection
Red blood cells	0-2 per optical field	Urine infection Acute tubular necrosis Benign prostatic hypertrophy Hemorrhagic cystitis Pyelonephritis Glomerulonephritis Drugs
Bacteria	Rarely present	Urine infection
Epithelia	Rarely present	Urine infection Vaginal excretions
Casts	Rarely present	Leukocytic: Pyelonephritis Epithelial: Acute tubular necrosis Eclampsia Heavy metal poisoning Interstitial nephritis Erythrocytic: Glomerulopathy Vasculitis Hyaline: Strenuous exercise Chronic renal failure Congestive heart failure Proteinuria Malignant hypertension Granular: Renal failure Glomerulonephritis Malignant hypertension Pyelonephritis Fatty: Chronic renal disease Diabetes mellitus Hypothyroidism Nephrotic syndrome
Crystals	Rarely present	ACIDIC URINE Uric acid crystals: Nephrolithiasi Acute nephropathy resulting from lymphoproliferative or myeloproliferative disorders. Calcium oxalate crystals: Chronic renal disease Nephrolithiasis Acute renal failure Idiopathic hyperoxaluria After consumption of chocolate or nuts Cystine crystals: Cystinuria Tyrosine crystals: Tyrosinemia Hepatic disease Leucine crystals: Hepatic disease ALKALINE URINE Calcium phosphate crystals Diet high in calcium Urine infection Thyroid gland diseases Ammonium urate crystals: No clinical significance Magnesium ammonium phosphate crystals: Urinary tract infections caused by urease producing microorganisms such as Proteus, Klebsiella, Staphylococcus, Pseudomonas.

Additional information

The first urine voided in the morning is preferred because of its high condensation as well as its acidic pH, factors that help preserve all urine elements.
The sample must be collected in the middle of urination because, this way, the possibility of contamination with epithelial cells and bacteria carried away from the urethra at the beginning of urination, is reduced.