Question
click below
click below
Question
Normal Size Small Size show me how
Urinalysis Chapter 3
Physical Examination of the Urine
Question | Answer |
---|---|
What determines the physical examination of urine? | Color, clarity, specific gravity, Osmolarity, and volume if timed. |
What are the common colors of urine? | Pale yellow, yellow, dark yellow, and amber. |
What is the yellow color of urine caused by? | the presence of a pigment, named urochrome. |
What is urochrome? | is a product of endogenous metabolism, and under normal conditions the body produces it at a constant rate. |
What is uroerythrin? | A pink pigment present in urine in smaller amounts, and it is most evident in specimens that have been refrigerated, resulting in the precipitation of amorphous urates. |
What is urobilin? | is an oxidation product of the normal urinary constituent urobilinogen, imparts an orange-brown color to urine that is not fresh. |
What does Dark yellow/Amber/Orange urine mean? | It can be caused by the presence of the abnormal pigment bilirubin. |
What do techs do if it is suspected that specimen contains bilirubin? | It is shaken and a yellow foam appears. |
What does yellow-orange specimen mean? | it is caused by the administration of phenazopyridine(Pyridium) or azo-gantrisin compounds to persons with urinary tract infections. |
What does Red/Pink/Brown urine mean? | blood in urine. |
What color is produced when the oxidation of hemoglobin to methemoglobin has occured from urine remaining in an acidic conditions for several hours? | brown |
What does a fresh brown color mean when the urine contains blood indicate? | It could indicate glomerular bleeding resulting from the conversion of hemoglobin to methemoglobin. |
If RBC are present what does the urine look like and if it's myoglobin? | it's red and cloudy and if myoglogin is present it's red and clear. |
What does hemoglobinuria mean? | it's resulting from the in vivo breakdown of RBC and is accompanied by red plasma. |
What does the breakdown of skeletal muscle produce? | myoglobin |
How does urine specimens appear of they contain porphyrins and why? | appear red from the oxiation of porphobilinogen to porphyrins, they are referred to as port wine. |
What does brown/black urine mean? | if negative chemical results for blood, they many contain melanin or homogentisic acid. |
What is melanin? | an oxidation product of the colorless pigment, melanogen, produced in excess when an malignant melanoma is present. |
What does homogentisic acid mean? | a metabolite of phenylalanine, imparts a black color to alkaline urine from persons with the inborn-error of metabolism called alkaptonuria. |
What are some of the medications that produce black/brn urine? | levodopa, methyldopa, phenol derivatives, and metronidazole. |
What does it mean to have blue/green urine? | a pseudomonas infection and intestinal tract infections. |
What does clarity refer to? | is a general term that refers to the transparency/turbidity of a urine specimen. |
Clarity if determined by? | visually examining the mixed specimen while holding it in front of a light source. |
What is some of the common terminology when reporting clarity? | clear, hazy, cloudy, turbid, and milky. |
What do precipitation of amorphous phosphates and carbonates cause? | a white cloudiness. |
What are the causes of cloudy urine? | Temperature(cold,refrigerator storage), pink turbidity(acid pH) - urates. |
What does hazy clarity mean? | Few particulates, print easily seen through urine. |
What does cloudy clarity mean? | Many particulates, print blurred through urine. |
What does turbid mean? | Print cannot be seen through urine. |
What does milky clarity mean? | May precipitate or be clotted. |
What are some of the nonpathologic causes of urine turbidity? | Squamous epithelial cells, mucus, amorphous phosphates, carbonates, urates, semen, spermatozoa, fecal contamination, radiographic contrast media, talcum powder, and vaginal creams. |
What are some of the pathologic causes of turbidity? | RBC, WBC, and bacteria caused by infection or a systemic organ disorder, yeast, nonsquamous epithelial cells, abnormal crystals, lymph fluid and lipids. |
What is the current criteria used to determine the necessity of performing a microscopic examination on urine specimen? | both clarity and chemical test for RBC, WBC, bacteria and protein. |
The ability of the kidneys to selectively reabsorb essential chemicals and water from the glomerular filtrate is one of the body's most important functions. True or False | True |
What is specific gravity defined as? | the density of a solution compared with the density of a similar volume of distilled water at a similar temperature. |
What is specific gravity of urine defined as? | is a measure of the density of the dissolved chemicals in the specimen. |
What is the normal range for SG? | 1.005-1.030 |
What is the measure of SG influenced by? | number of particles and size of particles. |
What are some of the methods for measuring SG? | direct methods: using a urinometer, harmonic oscillation densitometry(HOD) and indirectly by usina a refractometer or the chemical reagent strip. |
Explain the urinometer? | consists of a weighted float attached to a scale that has been calibrated in terms of urine specific gravity. the level to which the urinometer sinks represents the specimen's mass or specific gravity. |
Name the disadvantage of using the urinometer? | requires a large volume of 10 to 15mL, must be corrected for temperature(0.001 for every 3 degrees C) must be correcte for high levels of protein(subtract .003 for every gram of protein) glucose(subtract .004 for every gram of glucose) |
Explain the refractometry? | determines the concentration of dissolved particles in a specimen, does this by measuring the refractive index. |
What is a refractive index? | a comparison of the velocity of light in air with the velocity of light in a solution. |
What does the concentration of dissolve particles present in solution determine? | the velocity and angle at which light passes through a solution. |
What are the advantages of the refractometer? | requires only 2 drops of urine, temperature corrections are not necessary, reads refractive index. |
How do you calibrate the refractometer? | Using distilled water that should read 1.000, 9% sucrose solution should read 1.033-1.035, 5% NaCl solution should read 1.021-1.023, use a zero set screw to adjust reading. |
What do the 3 scales in the refractometer mean? | urine specific gravity (far left) starts with 1.000; serum protein (center scale gm%); and refractive index (far right) starts with 0.000 |
If the specific gravity is >1.035 what must you do? | dilute the specimen |
If you make a 1:2 dilution of a urine specimen and the result now reads 1.018 on the diluted specimen on the refractometer, what is the reported result? | 1.036 |
Explain urine odor? | It's not routinely reported, an ammomnia smell usually indicates presence of bacteria versus sample integrity(older than 1 hour) |
What does a fruity odor indicate? | acetone found in patients in diabetic ketoacidosis. |
What does an maple syrup odor indicate? | branched chain amino acids a serious metabolic defect, it includes amino acids leucine, isoleucine, and valine. |
What are the disadvantages and advantages uring a dip stick for measuring SG? | Disadvantages: measures only in 0.005 increments, and cost. Advantages are it's faster. |
What does Osmolarity mean? | weight per volume |
What does Osmolality mean? | Weight per weight |
What is the formula for Osmolarity? | MW/#ions=osmolarity (gm/osmole) |
What is the osmolarity of NaCl? | NaCl->Na+Cl-MW=58.5/2=29.25 gm/osmole |
What is the osmolarity of glucose? | Glucose does NOT dissociateMW=180/1=180 gm/osmole |
Osmolality ranges and unit conversions | 1 osmole= 1000 milliosmolesNormal ranges:-serum: 275-300 milliosmoles-urine: 50-1400 milliosmoles |
If one mole of NaCl is dissolved in 1 kg of water depresses the Freezing point -3.49C, calculate the osmolarity: | 1000mOsm/-1.86 = XmOsm/-3.46 X=1860 mOsm. |
The concentration of a normal urine specimen can be estimated by which of the following? | Color |
The normal yellow color of urine is produced by: | Urochrome |
A yellow-brown specimen that produces a yellow foam when shaken can be suspected of containing: | bilirubin |
A urine that turns black after standing may contain: | Homogentisic acid, Melanin, and Methemoglobin. |
Specimens that contain intact RBCs can be visually distinguihed by those that contain hemoglobin because: | RBC produce a cloudy specimen |
After eating beets purchased at the local farmers' market, Mrs. Williams notices that her urine is red, but Mr. William's urine is remains yellow. The williamses should: | Not be concerned because only Mrs. Williams is genetically susceptible to producing red urine from beets. |
Specimens from patients receiving treatment for urinary tract infections frequently appear: | Viscous and Orange |
Freshly voided normal urine is usually clear; however, if it is alkaline, a white turbidity may be present due to: | Amorphous phosphates and carbonates |
Microscopic examination of a clear urine that produces a pink precipitate after refrigeration will show: | Amorphous urates |
Under what conditions will a port-wine urine color be observe in a urine specimen? | urine contains porphyrins |
Which of the following specific gravities would be most likely to correlate with a dark yellow urine? | 1.030 |
True or False: Urine specific gravity is equally influenced by the presence of glucose and sodium. | False |
In what circumstance might a sediment be slightly warmed prior to microscopic examination? | To dissolve amorphous urates |
A urine specific gravity measured by refractometer is 1.029, and the temperature of the urine is 14 degrees C. The specific gravity should be reported as: | 1.027 |
Refractive index compares: | Light velocity in air with light velocity in solutions. |
Refractometers are calibrated using: | Distilled water and sodium chloride |
A correlation exist between a specific gravity of 1.050 and a: | Radiographic dye infusion |
An alkaline urine turns black upon standing, develops a cloudy white precipitate, and has a SG of 1.012. The major concern about this specimen would be: | Color |
The reading of distilled water by the refractometer is 1.003. You should: | Adjust the set screw |
A urine specimen with a specific gravity of 1.008 has been diluted 1:5, the actual specific gravity is: | 1.040 |
The method for determining a urine specific gravity that is based on the principle that the frequency of a sound wave entering a solution changes in proportion to the density of the solution is: | Harmonic Oscillation Densitometry |
A specimen with a specific gravity of 1.005 would be considered: | Hyposthenuric |
True or False: Specific gravity is of more diagnostic value than osmolarity in evaluating renal concentration ability. | False |
A strong odor of ammonia in a urine specimen coul indicate: | Urinary tract infection |
The microscopic of a cloudy amber urine is reported as rare WBCs and epithelial cells. What does this suggest? | A possible mix up of specimen and sediment |
A specimen with a strong ammonia odor and a heavy white precipitate when it arrives in the laboratory may require: | collection of a fresh specimen. |