AUBF PRELIMS

1200 to 1500 ml (or 600 to 2000ml)

Normal daily urine output range

Oliguria

Decrease in urine output (less than 1ml/kg/hr in infants, less than 0.5 ml/kg/hr in children and less than 400 ml in adults). Seen commonly when the boy enters a state of dehydration as a result of excessive water loss from vomiting, diarrhea, perspiration, or severe burns. May lead to anuria as a result from serious damage to kidneys.

Nocturia

Increase in the nocturnal excretion of urine.

Polyuria

Increase in daily urine volume (greater than 2.5L/day in adults and 2.5 to 3 mL/kg/day in children) is often associated with diabetes mellitus and diabetes insipidus, however, it may be induced artificially by diuretics, caffeine, or alcohol, all of which suppress the secretion of ADH.

Urea

Primary organic component of urine. Product of metabolism of protein and amino acids.

Creatinine

Product of metabolism of creatine by muscles

Uric acid

Product of breakdown of nucleic acid in food and cells

Chloride

Primary inorganic component, Found in combination with sodium and many other inorganic substances

Sodium

Primarily from salt, varies by intake.

Potassium.

Combined with chloride and other salts

Phosphate

Combines with sodium to buffer the blood

Ammonium

Regulates blood and tissue fluid acidity

Calcium

Combines with chloride, sulfate, and phosphate

Diabetes insipidus

Results from a decrease in the production or function of ADH. Urine is truly dilute and has a low specific gravity.

Modified/darkened color

Oxidation or reduction of metabolites

Decreased clarity

Bacterial growth and precipitation of amorphous material

Increased ammonia smell

Bacterial multiplication causing breakdown of urea to ammonia

Increased pH

Breakdown of urea to ammonia by urease producing bacteria/loss of CO2.

Decreased glucose

Glycolysis and bacterial use

Decreased ketones

Volatilization and bacterial metabolism

Decreased bilirubin

Exposure to light/photo oxidation to biliverdin

Decreased urobilinogen

Oxidation to urobilin

Increased nitrite

Multiplication of nitrate reducing bacteria

Decreased RBC and WBC

Disintegration/lyse in dilute alkaline urine

Decreased trichomonas

Loss of motility, death.

Refrigeration

Does not interfere with chemical tests. Precipitates amorphous phosphates and urates. Prevents bacterial growth for 24 hours.

Acids (boric acids, HCL, acetic acid, tartaric acid)

Prevents bacterial growth and metabolism. Interferes with analysis of drugs and hormones. Keeps pH at 6.0. Can be used for transport of urine cultures

Formalin (formaldehyde)

Excellent sediment preservative. Acts as a reducing agent, interferes with glucose, blood, leukocyte esterase, and copper reduction. Rinse specimen container to preserve cells and casts.

Sodium fluoride

Good preservative for drug analyses. Inhibits reagent strip tests for glucose, blood, and leukocytes.

Commercial preservative tablets

Convenient when refrigeration not possible. Have controlled concentration to minimize interference. Check composition to determine possible effects on desired tests

Urine collection kits (Becton, Dickinson, Rutherford, NJ).

Contains collection cup, transfer straw, culture and sensitivity, preservative tube, or UA tube.

Light gray and gray C&S tube

Specimen stable at room temperature for 48 hours; prevents bacterial growth and metabolism. Do not use if urine is below minimum fill line. Preservative is boric acid, sodium borate, and sodium formate. Keeps pH at about 6.0

Yellow UA Plus tube

Used on automated instruments. Must refrigerate within 2 hours. Round or conical bottom, no preservative.

Cherry red/Yellow preservative plus tube

Specimen stable for 72 hours at RT; instrument compatible. Must be filled to minimum fill line. Preservative is sodium propionate, ethyl paraben, and chlorhexidine. Round or conical bottoms.;

Random specimen

Most commonly received specimen. Useful for routine screening tests, but may show erroneous results from dietary intake or physical activity.

First morning specimen

The “ideal” screening specimen. Also essential for preventing false-negative pregnancy tests and for evaluating orthostatic proteinuria. Concentrated specimen, thereby assuring detection of chemicals and formed elements taht may not be present in a dilute random specimen.

24 hour (or timed) specimen

Used for quantitative chemical tests. Patient must begin and end the collection period with an empty bladder. It is mixed thoroughly and the volume accurately measured and recorded. All specimens should be refrigerated or kept on ice during the collection period and may require addition of a chemical preservative.

Catheterized specimen

This specimen is collected under sterile conditions by passing a hollow tube through the urethra into the bladder. Most commonly used for bacterial culture

Midstream clean catch

Provides a safer, less traumatic method for obtaining urine for bacterial culture and routine urinalysis. Provides a specimen that is less contaminated by epithelial cells and bacteria. More representative of the actual urine than the routinely voided specimen.

Suprapubic aspiration

Provides a specimen for bacterial culture taht is completely free of extraneous contamination. Also used for cytological examination

Three glass collection

First urine passed is collected in a sterile container. Midstream portion is collected in second container, prostate fluid is passed with remaining urine into a third sterile container. Quantitative cultures are performed on all specimens. 1st and 3rd are examined microscopically. Third specimen will have high WBC and bacteria in prostatic infection. Second specimen is control for bladder and kidney infection

Pre and Post massage test

Clean catch midstream urine specimen is collected. A second urine sample is collected after prostate is massaged. Positive significant bacteriuria in the postmassage specimen of greater than 10 times the premassage count.

Stamey-Meares test for prostatitis.

First urine specimen is voided bladder (VB1) which is the first 10 ml of urine and represents the urethral specimen. Patient then voids another 100 to 150 ml of urine. Second specimen VB2, is collected which is another 10 ml and represents bladder specimen. The third specimen (EPS) is collected during prostatic massage. Fourth specimen (VB3), consists of 10 ml urine collected after EPS, It contains any EPS trapped in the prostatic urethra. Urethral infection or inflammation is tested by VB1, and VB2 tests for urinary bladder infection. Prostatic secretions are cultured and examined for wbc. more than 10 to 20 wbc per hpf is considered abnormal.

Cortical nephrons

Make up approximately 85% of nephrons. Situated primarily in the cortex of the kidney. Responsible primarily for removal of waste products and reabsorption of nutrients.

Juxtamedullary nephrons

Have longer loops of Henle that extend deep into the medulla of the kidney. Primary function is concentration of the urine.

1. Renal artery

2. Afferent arteriole

3. Glomerulus

4. Efferent arteriole

5. Peritubular capillaries

6. Vasa recta

7. Renal vein

Renal blood flow

Bowman capsule

Forms the beginning of the renal tubule, it is where the glomerulus is located.

RAAS (Renin-Angiotensin-Aldosterone System)

Regulates the flow of blood to and within the glomerulus. This system responds to changes in blood pressure and plasma sodium content that are monitored by the juxtaglomerular apparatus

Renin

Enzyme produced by the juxtaglomerular cells, which reacts with angiotensinogen to product angiotensin I.

Angiotensin-converting enzyme (ACE)

Changes angiotensin I to its active form angiotensin II.

Angiotensin II

Corrects renal blood flow by:

1. Causing vasodilation of the afferent arterioles and constriction of efferent arterioles

2. Stimulating reabsorption of sodium and water in the proximal convoluted tubules

3. Triggering the release of the sodium-retaining hormone aldosterone by the adrenal cortex and antidiuretic hormone by the hypothalamus

1.010

The filtrate leaving the glomerulus has a specific gravity of?

Active transport

Glucose, amino acids, and salts in the proximal convoluted tubule, Chloride in the ascending loop of henle, and Sodium in the distal convoluted tubule is absorbed through which type of transport?

Passive transport

Water in the PCT, descending loop of henle, and collecting duct, Urea in the PCT, and ascending loop of henle, Sodium in the ascending loop of henle is reabsorbed through which type of transport

Passive transport

Takes place in all parts of the nephron except the ascending loop of Henle.

Renal threshold

The plasma concentration at which active transports stops

160 to 180 mg/dL

Glucose plasma threshold

Tubular damage

Glucose appearing in the urine of a person with a normal blood glucose level is the result of ______ and not diabetes mellitus

Renal concentration

Begins in the descending and ascending loops of Henle, where the filtrate is exposed to the high osmotic gradient of the renal medulla.

Antidiuretic hormone (vasopressin)

Renders the walls of the distal convoluted tubule and collecting duct permeable or impermeable to water. A high level increases permeability, resulting in increased reabsorption of water, and a low volume concentrated urine. The absence of this renders the walls impermeable to water, resulting in a large volume of dilute urine.

Tubular secretion

Involves the passage of substances from the blood in the peritubular capillaries to the tubular filtrate. Serves two major functions: eliminating waste products not filtered by the glomerulus and regulating the acid-base balance in the body through the secretion of hydrogen ions.

Glutamine

In the proximal convoluted tubule, ammonia is produced from the breakdown of the amino acid _________

Metabolic acidosis or renal tubular acidosis

The inability to produce an acid urine

Glomerular filtration tests

Standard tests used to measure the filtering capacity of the glomeruli are termed ________. Measures the rate in ml per minute at which the kidneys are able to remove a filterable substance from the blood. The substance must be one that is neither reabsorbed nor secreted by the tubules

Inulin

A polymer of fructose. Extremely stable substance that is neither reabsorbed nor secreted by the tubules. It is not a normal body constituent, it is infused by IV at a constant rate. It was the original reference method for clearance tests.

Exogenous procedure

Clearance test that requires an infused substance

Creatinine

Waste product of muscle metabolism that is produced enzymatically by creatine phosphokinase from creatine, which links with ATP to produce ADP and energy

Gentamicin, cephalosporins, and cimetidine (Tagemet)

Medications that inhibit tubular secretion of creatinine, thus causing serum levels that are falsely low.

Cystatin C

Small protein produced at a constant rate by all nucleated cells; it is filtered readily by the glomerulus and reabsorbed and broken down by the renal tubular cells. It is not secreted by the tubules, and the serum concentration can be related directly to the GFR. It is recommended for pediatric patients, diabetics, elderly, and critically ill patients. It is independent of muscle mass.

Beta2-Microglobulin

11800 MW. Dissociates from human leukocyte antigens at a constant rate and is removed rapidly from the plasma by glomerular filtration. May be used to distinguish disorders of the kidney as either glomerular or tubular. Its excretion in urine is normally low, but when renal tubules are damaged, it increases.

Tubular reabsorption

It is often the first function affected in renal disease.

Concentration tests

Tests to determine the ability of the tubules to reabsorb essential salts and water that have been nonselectively filtered by the glomerulus.

Osmolality

Measures only the number of particles in a solution.

Freezing-Point osmometers

First principle incorporated into clinical osmometers. Determines the freezing point of a solution by supercooling a measured amount of sample to approximately 27C.

Vapor pressure osmometes

Used primarily to analyze serum and sweat microsamples for disorders not related to renal function, such as cystic fibrosis. They are used primarily in the chemistry department. The dew point is measured.

P-aminohippuric acid test

Most common test for tubular secretion and renal blood flow.

Colorless

Recent fluid consumption. Commonly observed with random specimens.

Pale yellow

Polyuria or diabetes insipidus (increased 24 hour volume and low specific gravity). Diabetes mellitus (elevated specific gravity and positive glucose test result)

Dilute random specimen (Recent fluid consumption)

Dark yellow

Concentrated specimen, may be normal after strenuous exercise or in first morning specimen. B complex vitamins, Dehydration, fever or burns. Bilirubin (Yellow foam when shaken and positive chemical tests results for bilirubin)

Acriflavine (Negative bile results and possible green fluorescence)

Nitrofurantoin (Antibiotic administered for urinary tract infections)

Orange-yellow

Phenazopyridine (pyridium) - drug commonly administered for urinary tract infections.

Phenindione - anticoagulant, orange in alkaline, colorless in acidic.

Sulfasalazine (Azulfidine) - anti-inflammatory drug

Yellow-green

Bilirubin oxidized to biliverdin. Colored foam in acidic urine and false negative chemical test results for bilirubin.

Green

Pseudomonas infection. Asparagus/

Blue-green

Amitriptyline (antidepressant)
Methocarbamol (Robaxin) - muscle relaxant (green-brown)

Clorets

Indican - bacterial infections

Methylene blue - fistulas

Phenol

Propofol (anesthetic)

Familial hypercalcemia “blue diaper syndrome”

Indomethacin (Indocin, Tivorbex) - NSAID

RBCs

Cloudy urine pink/red urine with positive chemical tests results for blood and RBCs visible microscopically

Hemoglobin

Clear urine with positive chemical tests for blood; intravascular hemolysis

Myoglobin

Clear urine with positive chemical test results for blood; muscle damage

Beets

Causes pink/red urine. Alkaline urine of people who are genetically susceptible.

Rifampin

Causes pink/red urine. Tuberculosis medication

Port wine

Caused by porphyrins. Negative test for blood.

Red-brown

RBCs oxidized to methemoglobin. Seen in acidic urien after standing; positive chemical test result for blood. Myoglobin.

Brown/Black

Homogentisic acid (alkaptonuria)

Malignant melanoma/melanin - urine darkens on standing and reacts with nitroprusside and ferric chloride.

Phenol derivatives - interferes with copper reduction tests

Argyrol - antiseptic, disappears with ferric chloride

Methyldopa or leovodopa

Metronidazole/Flagyl - darkens on standing

Chloroquine and primaquine

Methocarbamol

Fava beans, rhubarb or aloe

Urochrome

Product of endoenous metabolism, the body produces it at a constant rate. Increases in urine that stands at room temp.

Uroerythrin

Pink pigment, most evident in specimens that have been refrigerated, resulting in the precipitation of amorphous urates in an acid urine.

Urobilin

Oxidation product of urobilinogen, imparts an orange brown color to urine that is not fresh.

SMAS FRTV

Squamous epithelial cells

Mucus

Amorphous substances

Semen, spermatozoa

Fecal contam

Radiographic contrast media

Talcum powder

Vaginal powder

Nonpathological causes of urine turbidity

RWBY TNALL

RBCs

WBCs

Bacteria

Yeast

Trichomonads

Nonsquamous epithelial cells

Abnormal crystals

Lymph fluid

Lipids

Pathological causes of urine turbidity

Isosthenuric

Used to describe urine with a SG of 1.010.

Hyposthenuric

Urine specimens that have a SG of below 1.010

Hypersthenuric

Urine specimens that have a SG above 1.010

Refractometry

Determines the concentration of dissolved particles in a specimen by measuring refractive index.