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Flashcards in 3 Deck (62):
1

What is a "dipstick" used for?

Basic diagnostic tool used to determine pathological changes in a patient's urine in standard urinalysis

2

How long does it take before you can read a dipstick?

60-120 seconds after the dip

3

How do the plastic strips (dipstick) testing work?

Plastic strips have pad that contain chemicals that react with certain compounds in the urine producing a specific color. (Paper strips are specific to a single reaction)

4

For accurate dipstick results, what should you do?

Store reagent strips in their bottle with lid closed at room temperature, this prevents the loss of sensitivity of reagent strips

5

What should you not expose dipsticks to?

- Sunlight
- Heat
- Cold
- Volatile Substances
- Moisture

6

When using a dipstick, when should you test urine?

Test urine which is brought to room temperature and well-mixed urine

7

What would discoloration of the strip indicate?

Significant loss of reactivity

8

What do the kidneys and lungs regulate?

Acid-base balance of the body

9

The pH of the urine is a reflection of _____

The ability of the kidneys to maintain normal hydrogen ion concentration in plasma and extracellular fluid

10

What are the 2 main objectives of urine pH?

1) Diagnostic (e.g. metabolic abnormalities)

2) Therapeutic (e.g. regulation of diet or medications)

11

What does urine pH normally fluctuate between?

Acidic and Alkaline

12

Acid indicator =

Methyl Red

13

Alkaline Indicator =

Bromthymol blue

14

pH of urine ranges from ______

5.0 to 8.5** in half units (commercial dipstick)

15

When your protein intake is high, what happens on your urine dipstick?

More phosphates, sulfates are produced which results in more acidic urine

16

Vegetable diet normally results in urine pH of _____

> 6

17

What is the large list of factors that result in acidity?

- Dehydration
- Diarrhea
- Fever
- Diabetes Ketoacidosis
- Gout
- Pulmonary Emphysema
- High protein diets or cranberries
- Renal Tubular Acidosis (proximal tubular, distal tubular) metabolic acidosis
- Acidifying drugs (for ammonium magnesium stone prevention)

18

What is the long list of factors that result in alkalinity (urine)?

- Acute and chronic renal failure
- Urinary tract infections
- Bacterial contamination of urine
- Alkaline drugs
- Diuretics

19

What is the source of low molecular weight protein that could be found in the urine?

Genito-urinary tract

20

Describe Mucoprotein Tamm-Horsfall (T-H):****

It is secreted by the renal tubules (renal epithelial cells) and is not derived from blood plasma ****

21

In regards to urine protein, what amount of T-H protein is excreted?**

Less than 150mg/24 hr (or 20mg/dL) ****

22

What is T-H protein?

It is a matrix for formation of calculi or casts

23

When testing for protein in urine, what is the principle it is based on called?

"Protein Error of pH indicators" ***

24

What is Protein Error of pH indicators?

Ability of protein to alter the color of some acid-base indicators without altering the pH

25

In a solution void of protein, ______

Tetrabromphenol blue, buffered at a pH of 3, is yellow

26

In the presence of protein (albumin), what happens when testing urine protein?

The color changes to green, then blue, depending on the concentration

27

The method of "Protein Error of pH Indicators" is more sensitive to ______ *****

Albumin than to globulin ***

28

The principle, "Protein error of pH indicators"most common indicator?

Tetrabromphenol blue

29

Protein error of pH indicators detects primarily _____

albumin

30

What would a false positive in urine protein result from?

- Highly buffered alkaline urine (medications or old urine
- Prolonged exposure to the sample (too long)
- Container cleaning compounds (quaternary ammonia)
- Some skin cleaners
- blood in urine

31

What would a false negative in urine protein result from?

- Diluted urines
- Elevated amounts of proteins other than albumin

32

What factors could result in (temporary) proteinuria, (transient proteinuria, "trace")? ***

- Strenuous exercise
- Postural Proteinuria
- Dehydration
- Exposure to heat or cold
- Fever
- Emotional stress
- Pregnancy

33

What are diseases that can cause persistent proteinuria?

- Glomerulonephritis
- Pyelonephritis
- Malignant hypertension

34

Urine glucose is normally contained where?

In glomerular Ultrafiltrate

35

Where is 100% of glucose reabsorbed?

In the proximal tubules

36

Urine glucose is usually not present unless threshold levels exceed ______

160-180 mg/dl ****

37

The dipstick test is sensitive only to ____

GLUCOSE *, and other sugars do not give positive result

38

A false positive from urine glucose could develop from _____

After using oxidizing cleaning agents for urine containers:

- Peroxide
- Hypochlorite

39

A false positive of urine glucose occurs in patients taking what drug?

Levodopa (Parkinson's Disease)

40

When high levels of _____ are present in urine, this can create a false positive when testing urine glucose

KETONES***

41

A false negative in testing urine glucose could develop in:

- Cool urine
- Urine with high specific gravity due to uricosuria
- Alkaline urine due to bacterial contamination of old urine
- Ascorbic acid (Vitamin C) in high doses can inhibit the enzymatic reaction

42

When glucose is present in urine 2 hours after a sweet food, what is it known as?

Transient Glucosuria ***

43

What is Glucosuria dependent on?

- Blood glucose levels
- Glomerular filtration rate
- Tubular Reabsorption

44

Where is glucosuria seen in ?

Diabetes Mellitus and Congenital forms of glucosuria

45

Where does PERSISTENT glucosuria develop in? ***

- Diabetes Mellitus
- CNS problems (stroke, neoplasms)
- Kidney problems (uremia)
- Endocrine problems (e.g. acromegaly, pheochromocytoma)
- Liver disorders (e.g. glycogen storage disease)
- Pharmaceutical agents (e.g. diuretics, birth control pills)

46

What is a second method for measurement of sugar in urine?

Clinitest

47

What does clinitest measure?

Glucose and other reducing sugars which may be present (using a tablet that is dropped into the urine in a test tube)

48

What would give a false positive for clinitest?

- Ascorbic acid
- Cephalosporins
- Probenecid (treating gout and hyperuricemia)
- Urinary preservatives: formalin and formaldehyde

49

What are the characteristics of Clinitest?

It is accurate and reliable test for reducing substances
- Technique errors

50

What is a Benedict's test used to determine?

The presence of reducing sugars such as fructose, glucose, maltose, galactose, and lactose in urine

51

What is urine reducing sugar test?

It is a screening test for diagnosis of genetic disorders of carbohydrate metabolism

52

What test is routinely performed on urine for newborn children?

Urine reducing sugar test

53

What does urine reducing sugar test predominately detect (early screening)?

Galactosemia or diabetes ***

54

Where are ketones produced?

Normally by the liver as part of fatty acid metabolism

55

In normal states, urine ketones will be _____

completely metabolized

56

Describe why the body would create urine ketones:

If for any reason the body cannot get enough glucose for energy it will switch to using body fats, resulting in an increase in ketone production making them detectable in the blood and urine

57

Ketone bodies that commonly appear in the urine when fats are burned for energy are:

- Acetoacetic acid (20%)
- Beta-hydroxybutyric acid (78%)
- Acetone (2%) is lost in the air if a sample is left standing at room temperature

58

Urine should be tested ______ after collection of urine

immediately

59

Normally the urine should not contain a noticeable concentration of _____

Ketones to give a positive reading

60

In regards to urine ketones, the Dipstick test determines ____

The acetoacetic acid, or some brands of reagent strip also detects acetone

61

In regards to urine ketones, the dipstick doesn't detect ____

Beta hydroxybutyric acid

62

In regards to urine ketones, what may give a false positive or atypical color?

- Highly pigmented urine
- Combination of high specific gravity and low pH***
- Dehydration
- Phenylketones
- Some medications
- Abscrobic acid
- Positive and questionable results may be confirmed with a tablet test