Urinalysis - Fundamentals of Nursing Cli

8/2/2019 Urinalysis - Fundamentals of Nursing Cli

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Urinalysis is often part of an initial data basefor case work up of a clinically ill patient.

It is a very useful indicator and can provideinformation on the patient's:

carbohydrate metabolism,

kidney and liver function,

and acid-base balance.


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A urinalysis typically is accompanied by acomplete blood count and or a screening of

chemical panel for complete interpretation ofthe serum chemistries.


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When properly performed, the urinalysis is anenormously powerful tool. This simple set of

tests remains a key element for thelaboratory data base for every patientadmitted to the hospital. It is also a keyscreening test for the diagnosis of manycommon diseases such as diabetes.


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BilirubinuriaThe presence of bilirubin inurine

Functional proteinuria

Increased amount ofprotein excreted in the urine in associationwith high temperature, exposure to heat orcold, emotional stress and from excessiveexercise. This type of proteinuria is due torenal vasoconstriction.


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GlycosuriaAbnormal amounts of glucose inurine (also known asglucosuria)

Hematuria

The presence of intact red bloodcells in the urine

HemoglobinuriaPresence of hemoglobin inurine that could be due to infection such asmalaria or even incompatible transfusion


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KetonuriaThe presence of ketone bodies inurine. Ketone bodies found in urine are

acetone, diacetic acid (aceto-acetic acid) andbeta-hydroxybutyric acid.

NocturiaSecretion of more than 500 mL orurine at night with specific gravity less than1.018

OliguriaDecreased secretion of urine


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PolyuriaIncreased secretion of urine

Proteinuria (albuminuria)

An abnormal orincreased amount of protein, predominatelyin the form of albumin, in urine


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All routine urinalysis should begin with aphysical examination of the urine sample.

This examination includes assessment ofvolume, odor, and appearance (color andturbidity).


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Volume Urinary volume is dependent upon fluid intake;

amount of solutes to be excreted, primarily

sodium and urea; loss of body fluids by normalprocesses, such as perspiration and respiration,and abnormal processes, such as diarrhea; andcardiovascular and renal function. Although thevolume of a random specimen is clinicallyinsignificant, the volume of specimen receivedshould be recorded for purposes ofdocumentation and standardization.


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ODOR

Non-pathological, fresh urine has aninoffensive odor.


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Appearance (color and turbidity)

ColorThe color of urine is related, to a large

degree, by its degree of concentration. Thecolor of non-pathological urine varies widelyfrom colorless to deep yellow; the moreconcentrated the urine, the deeper the color.The color of urine is usually described aftervisual inspection with common color terms.
http://www.texascollaborative.org/spencer_urinalysis/ds_urine_color.htmhttp://www.texascollaborative.org/spencer_urinalysis/ds_urine_color.htm


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Urine Color The color of urine can vary from almost

colorless to black. Normal urine may showcolor variation ranging from pale yellow todeep amber. Urine color is typically a result ofthe degradation of the heme molecule into a

urinary pigment called urochrome.. Urobilinis produced from the oxidation ofurobilinogen and results in an orange-browncolor to urine that is not fresh.


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Two other pigments contributing to the colorof urine are uroerythrin and urobilin.

Uroerythrin is usually associated withamorphous urates in a refrigerated samplecausing the sample to exhibit a pinkcoloration


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Dietary pigments, drugs, and theirmetabolites and various other abnormal

substances may also contribute to thecoloration of the urine sample.


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TurbidityNormally freshly voided urine isclear. When urine is allowed to stand,

amorphous crystals, usually urates, mayprecipitate and cause urine to be cloudy. Theturbidity of urine should always be recordedand microscopically explained.


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Red Blood Cells

Hematuria is the presence of abnormal

numbers of red cells in urine due to:glomerular damage, tumors which erode theurinary tract anywhere along its length,kidney trauma, urinary tract stones, renalinfarcts, acute tubular necrosis, upper andlower urinary tract infections, nephrotoxins,and physical stress.


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Red cells may also contaminate the urinefrom the vagina in menstruating women orfrom trauma produced by bladdercauterization. Theoretically, no red cellsshould be found, but some find their way intothe urine even in very healthy individuals.

However, if one or more red cells can befound in every high power field, and ifcontamination can be ruled out, thespecimen is probably abnormal


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White Blood Cells

Pyuria refers to the presence of abnormal

numbers of leukocytes that may appear withinfection in either the upper or lower urinarytract or with acute glomerulonephritis.Usually, the WBC's are granulocytes.


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White cells from the vagina, especially in thepresence of vaginal and cervical infections, or

the external urethral meatus in men andwomen may contaminate the urine. If two ormore leukocytes per each high power fieldappear in non-contaminated urine, thespecimen is probably abnormal. Leukocyteshave lobed nuclei and granular cytoplasm.


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Epithelial Cells

Renal tubular epithelial cells, usually larger

than granulocytes, contain a large round oroval nucleus and normally slough into theurine in small numbers. However, withnephrotic syndrome and in conditions leadingto tubular degeneration, the numbersloughed is increased.


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Bacteria Bacteria are common in urine specimens

because of the abundant normal microbialflora of the vagina or external urethralmeatus and because of their ability to rapidlymultiply in urine standing at room

temperature. Therefore, microbial organismsfound in all but the most scrupulouslycollected urines should be interpreted in viewof clinical symptoms.


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Diagnosis of bacteriuria in a case ofsuspected urinary tract infection requires

culture. A colony count may also be done tosee if significant numbers of bacteria arepresent.


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Generally, more than 100,000/ml of oneorganism reflects significant bacteriuria.

Multiple organisms reflect contamination.However, the presence of any organism incatheterized or suprapubic tap specimensshould be considered significant.


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Yeasts

Yeast cells may be contaminants or represent

a true yeast infection. They are often difficultto distinguish from red cells and amorphouscrystals but are distinguished by theirtendency to bud. Most often they areCandida, which may colonize bladder,urethra, or vagina.


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Crystals Common crystals seen even in healthy patients

include calcium oxalate, triple phosphate

crystals and amorphous phosphates. Veryuncommon crystals include: cystine crystals inurine of neonates with congenital cystinuria orsevere liver disease, tyrosine crystals withcongenital tyrosinosis or marked liverimpairment, or leucine crystals in patients withsevere liver disease or with maple syrup urinedisease.


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Summary To summarize, a properly collected clean-catch,

midstream urine after cleansing of the urethral

meatus is adequate for complete urinalysis. Infact, these specimens generally suffice even forurine culture. A period of dehydration mayprecede urine collection if testing of renalconcentration is desired, but any specific gravity> 1.022 measured in a randomly collectedspecimen denotes adequate renal concentrationso long as there are no abnormal solutes in theurine.


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Another important factor is the interval oftime which elapses from collection to

examination in the laboratory. Changes whichoccur with time after collection include: 1)decreased clarity due to crystallization ofsolutes, 2) rising pH, 3) loss of ketone bodies,4) loss of bilirubin, 5) dissolution of cells andcasts, and 6) overgrowth of contaminatingmicroorganisms.


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Generally, urinalysis may not reflect thefindings of absolutely fresh urine if the

sample is > 1 hour old. Therefore, get theurine to the laboratory as quickly as possible.

Urinalysis - Fundamentals of Nursing Cli

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