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Microalbumin, Urine

Urine Albumin, Urine Microalbumin, Urine Albumin/Creatinine Ratio, Urine Microalbumin/Creatinine Ratio

Test Codes

Random: EPIC: LAB5089, Beaker: MALBU, Timed: EPIC: LAB689, Beaker: MALUT, 24-Hour: EPIC: LAB410, Beaker: MAL24

Department

Toxicology

Instructions

Note: 24-hour and random urine specimens MUST be collected separately. See below for collection criteria.

• Random Urine Microalbumin: Includes Microalbumin, Creatinine, and Microalbumin/Creatinine Ratio.
• Timed Urine Microalbumin: Includes Microalbumin, Creatinine, Microalbumin Excretion Rate, Microalbumin/Creatinine Ratio, Collection Period, and Total Volume.
• 24-Hour Urine Microalbumin: Includes Microalbumin, Creatinine, Timed Microalbumin, Microalbumin Excretion Rate, Microalbumin/Creatinine Ratio, Collection Period, and Total Volume.
• Please refer to the Specimen Collection Manual for instructions on 24-Hour or Random Urine Collection:
• Urine 24-Hour Collection - Inpatient
• Urine 24-Hour Collection - Outpatient
• Urine 24-Hour Collection - Outreach
• Random Urine Collection

Specimen Collection Criteria

Collect: 24-hour urine or timed urine specimen with a 24-hour urine container with no preservatives.
Also acceptable: Random urine specimen in a screw-capped container (preferred) or another sterile collection cup. Preservatives are not acceptable for random urine specimens. (Minimum: 20.0 mL)

• For patients who have difficulty collecting timed urines, a random urine sample for Microalbumin/Creatinine Ratio is suggested. A mid-stream collection from the first morning void is recommended. Other random samples are also acceptable.
• Refer to the table of Urine Preservative Options when multiple tests are requested.
• Keep 24-hour urine specimen iced or refrigerated during collection.
• Include start and end dates and times for the collection period on the specimen container.

Urine Preservative Options
No Preservative	6N Hydrochloric Acid	Boric Acid (10g)	Sodium Carbonate	50% Acetic Acid
Preferred	Unacceptable	Unacceptable	Unacceptable	Unacceptable

Physician Office/Draw Specimen Preparation

Maintain specimens refrigerated (2-8°C or 36-46°F) prior to transport.

Preparation for Courier Transport

Transport: Entire 24-hour urine collection, timed urine, or random urine, refrigerated (2-8°C or 36-46°F).

Rejection Criteria

• Specimens contaminated with blood (may result in falsely elevated results).
• Specimens not collected and processed as indicated.

In-Lab Processing

Measure total volume of 24-hour or timed urine specimen. Record total volume and collection start and end dates and times in the LIS system. Aliquot a minimum of 10.0 mL from the well-mixed 24-hour or timed urine collection.

Storage

Specimen Stability for Testing:

Room temperature (20-26°C or 68-78.8°F): 4 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): For longer storage.

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days (Royal Oak and Troy store an aliquot for 30 days.)

Laboratory

Dearborn Chemistry Laboratory
Farmington Hills Chemistry Laboratory
Grosse Pointe Chemistry Laboratory
Royal Oak Automated Chemistry Laboratory
Troy Chemistry Laboratory

Performed

Sunday – Saturday.
Results available within 24 hours.

Reference Range

Microalbumin: Less than 30 mg/24 hours.
Microalbumin Excretion Rate: Less than or equal to 20 mcg/minute.
Microalbumin/Creatinine Ratio: Less than 30 mg/g.

Test Methodology

Spectrophotometry, Immunoturbidimetry.

Interpretation

• Microalbumin is a term describing the presence of small amounts of albumin in the urine. A timed urine, either 24-hour or overnight (8-12 hour), if collected accurately, is probably the best method for detection of microalbumin.
• If a patient has =1+ proteinuria (30 mg/dL) by Urine Dipstick (Urinalysis), overt proteinuria is present and testing for microalbuminuria is inappropriate. In this situation a Urine Protein/Creatinine Ratio or a 24-hour urine collection for Total Protein is appropriate.

Clinical Utility

Microalbuminuria is an amount of albumin in the urine above normal (10 mg/L) but below that detected by dipsticks for urinary protein (greater than 30 mg/dL). Microalbuminuria has an important predictive value in determining diabetic patients at risk of developing nephropathy. Microalbuminuria may also be caused by poor metabolic regulation, physical exercise, newly diagnosed diabetes, hypertension, and non-diabetic renal or systemic disease.

Reference

1. Screening and Management of Microalbuminuria in Patients with Diabetes Mellitus: Recommendations. American Journal of Kidney Diseases. 25:107-112, 1995.

CPT Codes

82043, 82570.

Contacts

Last Updated

7/21/2024