URINALYSIS (UA)



URINALYSIS (UA)PROCEDURE:Urinalysis procedure is very standardized.First, the urine dipstick test is performed by dipping a test strip into the urine sample. After 2 minutes, all bands will be readable.Next, 10 cc of fresh urine is placed in a centrifuge at 2000 RPM for 5 minutes, in order to collect urine sediment.After 5 minutes, the test tube is removed from the centrifuge and 9.5 ccs of supernatant is poured out. One drop of sediment is placed on a slide and covered with a cover slip.The slide is viewed under light microscopy under low power and high power fields.Urine needs to be analyzed as soon as possible, preferably within 30 minutes.(Note: In clinic, we only perform the dipstick analysis)WHAT ARE WE LOOKING FOR?:General:Appearance: Urine should normally be clear.Cloudy urine may be indicative of a UTI.Color:Orange May be due to rifampin or contrast for a retinogram.Pink or red Indicates erythrocytes (hematuria), myoglobin (rhabdomyolysis), or some food colors.White Generally indicates pus (a UTI).Odor:Maple syrup Urine may smell sweet in Maple Syrup Urine Disease (MSUD).Musty or mousy A musty smell may be present due to PKU (phenylketonuria).Dipstick:Specific gravity: normal ~ 1.015If SG is low: hypotonic urine; this may indicate diabetes insipidus.If SG is high: hypertonic urine; this may indicate dehydration (may be normal) or diabetes mellitus.pH: normal ~ 5.5-6.5Urine pH is diet-dependent (tends to be acidic in a Western diet).A high pH (alkaline urine) may indicate a UTI (urea splitting organisms) or uric acid stones.A low pH (acidic urine) may indicate bacterial metabolism of glucose (diabetes mellitus).Blood: Blood in the urine (hematuria) is pathologic; dipstick should be “negative”.Hematuria may be microscopic or macroscopic.See light microscopy section for a detailed discussion of hematuria.Protein: A small amount of protein (proteinuria) in the urine is normal, but large amounts are pathologic. Normal excretion rate is ~ 80 mg/day, but may be higher in children (up to 200 mg/day).Proteinuria may occur due to fever, strenuous exercise, glomerular disease, diabetes mellitus, or several other systemic diseases.If protein is present in the urine in the setting of pregnancy, this may indicate preeclampsia.Note: Protein > 3 grams/day indicates nephrotic syndrome.Glucose: Under normal circumstances, there should be no glucose in the urine (glucosuria).Glucosuria may occur due to diabetes mellitus, Cushing’s syndrome, liver disease, pancreatic disease, or Fanconi’s Syndrome.Ketones: Ketones (products of fat metabolism) are normally not found in the urine. Acetoacetate and acetone (but not beta-hydroxybutyrate) may be found in the urine in the setting of uncontrolled diabetes mellitus (DKA), pregnancy, carbohydrate restriction (low carbohydrate diets), anorexia nervosa, and starvation.Nitrites: Nitrates are normally not found in the urine, and are derived from the reduction of nitrates to nitrites by bacteria.Note: not all bacteria are nitrite-producing. For example, N Gonnorrhoeae and M. Tuberculosis do NOT produce nitrites.Leukocyte esterase (LE): LE is produced by neutrophils and may be associated with a UTI.Bilirubin: Bilirubin is usually absent in urine. Conjugated bilirubin may be present in urine due to biliary obstruction.Urobilinogen: Urobilinogen is the end product of conjugated bilirubin after is has passed through the bile ducts and been metabolized in the intestine. It is normally present in small amounts in the urine.Elevated urobilinogen may be seen in hepatocellular disease and hemolysis.Low urobilinogen may be seen due to obstruction of the bile duct and broad-spectrum antibiotics.Note: if both leukocyte esterase and nitrite both negative, it is very unlikely (>97%) that a UTI is present. A great reference: ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download