Urinalysis, Microscopic, Osmolality, and pH
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Screening for urinary tract diseases and some nonrenal diseases
Profile Information A profile is a group of laboratory tests that are ordered and performed together under a single Mayo Test ID. Profile information lists the test performed, inclusive of the test fee, when a profile is ordered and includes reporting names and individual availability.
|Test ID||Reporting Name||Available Separately||Always Performed|
|UBIL||Bilirubin||Yes, (Order UBILU)||No|
|HGBQL||Hemoglobin, QL||Yes, (Order HGB_Q)||Yes|
|UREDU||Reducing Substance, U||Yes, (Only for internal practice)||No|
Reflex Tests Lists test(s) that may or may not be performed, at an additional charge, depending on the result and interpretation of the initial test(s)
|Test ID||Reporting Name||Available Separately||Always Performed|
Testing Algorithm Delineates situation(s) when tests are added to the initial order. This includes reflex and additional tests.
When this test is ordered, either automated or manual microscopic examination will always be performed at no additional charge.
UOSMU: Freezing Point Depression
PHU_: ph meter
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Crystal Identification, Urine
Crystal Identification, Urine
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Container/Tube: Plastic, 60-mL urine bottle
Specimen Volume: 20 mL
Collection Instructions: Collect a random urine specimen.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
The kidney plays a key role in the excretion of by-products of cellular metabolism and regulation of water, acid-base, and electrolyte balance. Urine is produced by filtration of plasma in the renal glomeruli followed by tubular secretion and/or reabsorption of water and other compounds.
Abnormalities detected by urinalysis may reflect either urinary tract diseases (eg, infection, glomerulonephritis, loss of concentrating capacity) or extrarenal disease processes (eg, glucosuria in diabetes, proteinuria in monoclonal gammopathies, bilirubinuria in liver disease).
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Red blood cells (RBCs), white blood cells (WBCs), renal tubular epithelial (RTE) cells, casts, squamous cells, parasites, fat, bacteria, and pathologic crystals are reported. RBCs are almost always indicative of glomerulonephritis. WBC casts are typically an indication of acute interstitial nephritis or pyelonephritis, but can also be seen in glomerulonephritides because there is often a component of accompanying interstitial nephritis. Fatty casts and free fat are often seen in patients with nephrotic syndrome or other glomerular diseases associated with significant proteinuria. Granular casts are observed in a number of disorders and are thought to be formed from partially degraded cellular casts, or are protein-derived casts. Hyaline casts are not thought to be indicative of any disease process, but increased numbers may be seen in concentrated urine specimens. Waxy casts and broad casts are most often observed in advanced renal failure. Increased numbers of RTE cells are indicators of renal tubular injury. Increased numbers of RTE cells may be caused by drugs with renal tubular toxicity (eg, cyclosporine A, aminoglycosides, cisplatin, radiocontrast media, acetaminophen overdose), interstitial nephritis, hypotension (surgical, sepsis, obstetric complications), and heme pigments from hemoglobinuria or myoglobinuria from rhabdomyolysis (eg, alcoholism, heat stroke, seizures, sickle cell trait). Newborns often shed RTE cells in their urine.
Based on careful review of all available published outcome studies with results of detailed hematuria workups within actual patient populations, a panel from the American Urological Association recommends that patients with >3 red cells per high-power field in 2 out of 3 properly collected urine specimens should be considered to have microhematuria, and hence evaluated for possible pathologic causes. However, the panel also noted that there is no absolute lower limit for hematuria, and risk factors for significant disease should be taken into consideration before deciding to defer an evaluation in patients with only 1 or 2 red blood cells per high power field. High-risk patients, especially those with a history of smoking or chemical exposure, should still be considered for a full urologic evaluation even after 1 properly performed urinalysis documented the presence of at least 3 red blood cells per high-power field. In certain patients, even 1 or 2 RBCs per high-powered field might merit evaluation. The presence of squamous cells suggests that the sample may not have been an optimal clean-catch specimen and could be contaminated with skin flora.
Osmolality is an index of the solute concentration of osmotically active particles, principally sodium, chloride, potassium, and urea. Glucose can contribute significantly to the osmolality when present in substantial amounts. The ability of the kidney to maintain both tonicity and water balance of the extracellular fluid can be evaluated by measuring the osmolality of the urine. More information concerning the state of renal water handling or abnormalities of urine dilution or concentration can be obtained if urinary osmolality is compared to serum osmolality. Normally, the ratio of urine osmolality to serum osmolality is 1.0:3.0, reflecting a wide range of urine osmolality. The reference ranges are as follows 0 to 12 months range is 50 to 750 mOsm/kg. >12 months of age range is150 to 1150 mOsm/kg. Please note above the age of 20 years there is an age dependent decline in the upper reference range of approximately 5 mOsm/kg/yr.
Urine pH is affected by diet, medications, systemic acid-base disturbances, and renal tubular function. pH may affect urinary stone formation. For example, urine pH <6.0 may help reduce the tendency for calcium phosphate stones and pH >6.0 may reduce the tendency for uric acid stone formation.
Produced during metabolism of fat. Increased ketones may occur during physiological stress conditions such as fasting, pregnancy, strenuous exercise, and frequent vomiting. Ketones may appear in the urine in large amounts, before serum ketone is elevated, under the following conditions:
- diabetic individuals who are unable to efficiently utilize glucose due to a lack of insulin
- individuals with other abnormalities of carbohydrate or lipid metabolism
Bilirubinuria is an indicator of liver disease and biliary tract obstruction.
Hemoglobinuria is an indicator of intravascular hemolysis. The test is equally sensitive to myoglobin as to hemoglobin (Hgb). The presence of Hgb, in the absence of RBCs, is consistent with intravascular hemolysis. RBCs may be missed if lysis occurred prior to analysis; the absence of RBCs should be confirmed by examining a fresh specimen. The presence of myoglobin may be confirmed by MYOU/9274 Myoglobin, Urine.
Urine can contain a variety of reducing substances (sugars [glucose, galactose, sucrose, fructose, lactose, maltose], ascorbic acid, drugs, etc), compounds so termed because of their ability to reduce cupric ions. The primary reducing substances of medical significance are the sugars, glucose (diabetes) and galactose (galactosemia). Other sugars may be found but are not of clinical significance. Because glucose also is detected by glucose-specific dipstick reagents, the test for reducing substances is performed to detect galactose.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Elevated specific gravity, elevated protein, and large amounts of ascorbic acid may cause false-negative results. Oxidizing substances such as hypochlorite and chlorine may cause false-positive results. The test is equally sensitive to hemoglobin and to myoglobin. The presence of Hgb, in the absence of RBCs, is consistent with intravascular hemolysis. RBCs may be missed if lysis occurred prior to analysis; the absence of RBCs should be confirmed by examining a fresh specimen. The presence of myoglobin may be confirmed by MYOU/9274 Myoglobin, Urine.
This test reacts with sufficient quantities of any reducing substance in the urine; it is not specific for glucose. Urine specimens with low specific gravity that contain glucose may give slightly elevated results. Metabolites of some sulfa drugs and methapyrilene compounds may interfere with the sensitivity of the test. X-ray contrast media in urine produces reduced and false-negative glucose results.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
Grossfeld GD, Litwin MS, Wolf JS, et al: Evaluation of asymptomatic microscopic hematuria in adults: the American Urological Association best practice policy-part I: definition, detection, prevalence, and etiology. Urology 2001;57:599-603
Method Description Describes how the test is performed and provides a method-specific reference
Ictotest tablet for Urinalysis (Package insert: Bayer Corporation, Diagnostics Division. Elkhart IN 46515)
Freezing point depression
AUTION Sticks 9EB for urine chemistry (Package insert: ARKRAY, Inc Japan, distributed by Iris Diagnostics Chatsworth,CA 91311-5874)
Performed on urine sediments by conventional microscopy or by automation using the IRIS iQ200. Determination of which method to use is made by visual inspection. If the urine is a clear, normal color and the amount is adequate (at least 30 mL), the urine is analyzed on the IRIS iQ200. All remaining urines have a manual microscopic examination done on the sediment after centrifuging for 5 minutes at 1400 RPM.
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Sunday; Continuously
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
|Result ID||Reporting Name||LOINC Code|
|UREDU||Reducing Substance, U||5809-9|