CHAPTER 13 (URINE)

Non-blood specimen labeling

Label these specimens immediately following collection in the presence of the patient using the same identifying information as blood specimens. In addition because many body fluids are similar in appearance, include the type and source (where it came from in the body) . Apply the label to the container, not the lid

Non-blood POCT quality control

Some of the non-blood tests in this chapter are waived noninstrumented (tests performed without using instruments) POCTs. Many of these tests are read visually. For example, an individual reads the color reactions on a strip after it is dipped into urine. For some of these tests, the manufacturer or institution may require that daily external liquid quality control be performed as a check on technique and accuracy of results.

Urine

The most frequently analyzed non-blood body fluid.

Its analysis can provide information on many of the bodies major metabolic functions. It can aid and monitoring wellness, The diagnosis and treatment of urinary tract infections, The detection and monitoring of metabolic diseases, And determining the effectiveness or complications of therapy.

Outpatient urine specimen collection is often handled by phlebotomists.

Types of urine specimens-random

Collected at any time and are the most convenient type. Used primarily for routine urinalysis and screening tests.

Types of urine specimens- first-morning/8 hour specimen

Collected immediately upon awakening in the morning after approximately eight hours of sleep. This type of specimen normally has a high specific gravity, which means that it is more concentrated than a random specimen. May contain substances and formed elements, such as cells and casts that would not be detected in a more diluted random specimen. This makes it the ideal specimen for most urine tests and the reason that first morning specimens are often requested to confirm the results of random specimens and specimens with low specific gravity.

Types of urine specimens- Fasting

Typically used for glucose monitoring. It differs from a first-morning specimen in that it is the second specimen voided after a period of fasting. This helps ensure that the specimen will not be affected by food consumed before fasting

Types of urine specimens- Timed

Collected at a specific time.

Two-hour

24-hour

Double voided

Two-hour postprandial (PP-after food) specimen

Collected two hours after a meal and tested for glucose. It is primarily used to monitor the insulin therapy of patients with diabetes. The patient is instructed to void shortly before consuming a normal meal and to collect a specimen two hours later. Results are often compared with glucose results on fasting urine and fasting blood specimens.

Twenty-four hour specimen

A pooled urine specimen collected over a 24 hour period to allow quantitative analysis of a urine analyte. Collection of the specimen requires a large clean, preferably wide mouth container capable of holding several liters. A special collection device that fits over the toilet and looks somewhat like an upside down hat is sometimes provided to the patient to make collection of the specimen easier.

Examples of 24hour tests- creatinine clearance (kidney function) and urobilinogen (liver function)

Collection and pooling of all urine voided in 24hours.

24 hour collection procedure

Void in a toilet as usual on waking, Note time and date on label and place on a container and begin timing, Collect all urine voided for the next 24 hours, Refrigerate specimens throughout the collection period, Collect urine before anticipated bowel movements, Drink normal amount of fluid unless instructed otherwise, Void one last time at the end of 24 hours, Seal container and transport to the lab ASAP

Some 24 hour specimens require collection under certain conditions or special handling such as:

-Preservatives added: some 24 hour specimens require the addition of a preservative before collection, Should be marked on the container

-Dietary restrictions: if testing for 5-HIAA (A product of the breakdown of serotonin that is measured in the diagnosis and monitoring of a type of tumor that produces serotonin), diet restrictions of foods containing serotonin content must not be eaten

-Refrigeration: creatinine clearance, quantitative porphyrins, and urine protein tests must be kept refrigerated throughout testing

-Drug interference: certain drugs can interfere with a 24 hour urine collection

Double voided specimen

Requires emptying the bladder and then waiting a specific amount of time (Typically 30 minutes) before collecting the specimen. It is most commonly used to test urine for glucose and ketones. Double voided specimens are thought to more accurately reflect the blood concentration of the analyte tested, Whereas a specimen that has been held in the bladder for an extended period may not.

Urine collection methods- Regular voided specimen

Requires no special patient preparation and is collected by having the patient urinate into a chemically clean urine container.

urine collection methods- Midstream specimen

Performed to obtain a specimen that is generally free of genital secretions, Pubic hair, And bacteria that normally surround the urinary opening. To collect the specimen, the patient voids the initial urine flow into the toilet. This initial flow helps flush contaminants from the urinary opening. The container is brought into the urine flow and a sufficient amount of urine is collected into a clean specimen container.

urine collection methods- midstream clean-catch specimen

Collected in a sterile container and yields a specimen that is suitable for microbial analysis for culture and sensitivity testing. These tests are necessary to ensure that the specimen is free of contaminating matter from the external genitalia areas. Special cleaning of the genital area is required before the specimen is collected

Urine collection methods- catheterized specimen

Specimen is collected from a sterile catheter inserted through the urethra into the bladder. A catheterize specimen is collected when a patient is having trouble voiding or is already catheterized for other reasons. Sometimes collected on babies to obtain a specimen for culture and sensitivity, On patients when vaginal contamination of the specimen is a concern, And on bedridden patients

Urine collection methods- suprapubic aspiration

Involves inserting a needle directly into the urinary bladder and aspirating (withdrawing by suction) the urine directly from the bladder into a sterile syringe. The specimen is then transferred to a sterile urine container. Normally requires the use of local anesthesia and is performed by a physician. Used for samples for microbial analysis or cytology studies.

Urine collection methods- pediatric urine collection

A plastic urine collection bag with hypoallergenic skin adhesive is used to collect urine from infants or small children who are not yet toilet trained. The patient’s genital area is cleaned and dried before the bag is taped to the skin. A diaper may be placed over the collection bag.

Common urine tests- routine urinalysis

The most requested your test because it screams for urinary and systemic disorders. Is this also the most performed point of care test. May be ordered as part of a patient’s physical examination or at various times during the hospitalization of a patient.

A routine UA typically includes physical, chemical, and microscopic analysis.

Avoid contamination by using midstream collection

First morning specimen is preferred

Collect in a clear dry chemically clean container

May be kept at room temperature for up to two hours or refrigerated.

Must be filled a min of 10mL

Routine UA-physical examination

macroscopic (visual) observation and notation of clarity (transparent, cloudy), color, odor, measurements, volume and SG or osmolarity.

Specific Gravity compares the density of urine to that of water. Osmolarity is a measure of dissolved particles.

Cloudy urine indicates bacteria or yeast.

Urine gets its color from urochrome- abnormal colors include bright yellow, brown, black, red, gray, and green

Routine UA- Chemical examination

Performed using a plastic reagent strip, often called a dipstick that contains absorbent pads impregnated with test reagents. Chemical reactions that result in color changes on the pads of the strip take place when the strip is dipped in the urine. The results are determined visually by comparing the colors against a color chart on the container. Results are typically reported using terms trace, 1+, 2+, and so on To indicate the degree of a positive result or a negative result with no reaction is not noted.

Tests for- bacteria, bilirubin, blood, glucose, ketones, leukocytes, nitrite, protein, urobilinogen, and measure pH and SG.

Routine UA- microscopic examination

Identify your components, such as cells, crystals, casts, and microorganisms by examining a sample of urine under a microscope.

A measured portion of well mixed urine centrifuged in a special plastic tube and then the supernatant (Clear top portion of the specimen) is discarded. A drop of the remaining sediment in the bottom of the tube is placed on a glass slide, called a cover slip and then examined under a microscope

Common urine tests- Culture and sensitivity

May be requested on a patient with symptoms of a UTI, such as frequent urge to urinate or pain when urinating. The culture involves placing a measured portion of urine on a special nutrient medium that encourages the growth of microorganisms, Incubating for 24 to 48 hours, Checking it for growth, And identifying any microorganisms that grow. A sensitivity or anabiotic test is performed to determine which antibiotics will be effective against the microorganism

Must be collected in a sterile container, following midstream clean-catch procedures to ensure that the specimen is free of contamination

Should be transported to the lab immediately if a delay in transportation or processing is unavoidable, the specimen should be refrigerated or preserved

Common urine tests- cytology studies

Perform to detect cancer, cytomegalovirus, And other viral and inflammatory diseases of the bladder and other structures of the urinary system.

Cells from the lining of the urinary track are shed into urine.

Smear containing these cells is prepared from urinary sediment or filtrate

Smear is stained by a papanicolaou (PAP) Method and examined under a microscope for abnormal cells

Fresh clean-catch specimen is required

Examine specimen ASAP after collection or preserve in alcohol

Common urine tests- drug screen

Performed to detect illicit (unlawful) use of recreational drugs

Drug screening can also be used to monitor therapeutic drugs in order to minimize drug withdrawal symptoms, and to confirm a diagnosis of drug overdose

Can screen up to 30 different drugs

Typically performed in groups based on drug classifications or families

Drug screening is performed mainly by urine samples because they are better to detect than blood samples and stay in the body longer than blood

A random sample in a chemically clean covered container is required for the urine drug test

Chain of custody protocol must be followed even if the test is not being done for legal reasons.

Pre-employment or routine work screenings

Common urine tests- ethical/alcohol testing

Urine is Not an ideal specimen for testing alcohol levels. Urine alcohol levels can indicate whether alcohol has been consumed within the past few hours.

Common urine tests- glucose and keto testing

Screens for diabetes and monitors glucose and ketone levels in diabetics.

Test strips are used to screen for diabetes

Glucose in urine- glycosuria. Glucose is not normally present in urine because the kidneys reabsorbed filter glucose back into the bloodstream

Ketones are created when the body breaks down fat for energy because the diet is deficient in carbohydrates, Or the body does not metabolize glucose properly. A buildup of ketones in the blood can lead to diabetic ketoacidosis

Common urine tests- Pregnancy testing

Pregnancy can be confirmed by testing urine for the presence of human chorionic gonadotropin, A hormone produced by cells within the developing placenta that appears in serum and urine approximately 8 to 10 days after conception. The first morning specimen is preferred because it is normally more concentrated and would therefore have a higher hCG concentration

Other urine tests

Chem tests such as electrophoresis, heavy metals, myoglobin clearance, creatinine clearance, and porphyrins. Many of these tests require a pooled, timed specimen, such as a 24 hour collection

Refractometer

Measures specific gravity