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Flashcards in Biochemical Testing Deck (34):
0

What process is solely responsible to water reabsorption throughout the entire nephron?

passive transport

1

Which method only measures the number of particles in solution?

Osmolality

2

How should you store reagent strips?

avoid exposure to moisture, chemicals, heat, and light, store at room temp below (30*C), keep desiccant packet inside bottle, and close vial immediately after use

3

When should QC be performed on the reagent strips?

use both pos and neg controls a minimum of once every 24 hours, when a new bottle of strips is opened, and when a new lot is received

4

What is the normal for Specific Gravity?

1.003 to 1.030

5

Urine with a specific gravity of 1.010

Isosthenuria

6

Urine with a specific gravity of < 1.010

Hyposthenuric

7

What is the most common cause of Hyposthenuria?

diabetes insipidus or renal disease

8

Urine with a specific gravity >1.010

Hypersthenuric

9

Limitation of specific gravity

only determines specific gravity from 1.000-1.030 in 0.005 increments

10

What lowers specific gravity readings?

highly buffered alkaline urine

11

How do you correct for alkaline urine?

when pH is > 7 add 0.005 to the strip reading if it is being read manually

12

Principle of pH

Double indicator of Methyl Red and Bromthymol Blue

13

Reference range for pH

There isn't a reference range for urine pH because broad variances occur daily in normal patients

14

When is acidic urine common during the day?

acidic urine is common in the morning (5-6)

15

WHen is urine suspicious of tampering as far as pH?

below 5 is suspicious

16

Meats and high protein diet lead to what pH in the urine?

acidic urine

17

Vegetarian diet leads to what type of pH in urine

alkaline urine

18

What is it called when you have basic urine after a large meal?

Alkaline Tide

19

What leads to ACIDIC blood and ALKALINE urine?

Renal tubular acidosis

20

what cells contain leukocyte esterase?

granulocytic white blood cells (neuts, eos, basos, and monos)
Not found in RBCs, Lymphocytes, and epithelial cells

21

Leukocyte Esterase Principle

Indoxylcarbonic acid ester > leukocyte esterase > indoxyl
indoxyl + diazonium salt >purple azodye

22

Leukocyte Esterase is associated with what infections?

Bacterial infections or Trichomonas infections

23

In bacterial infections with a positive leukocyte esterase, what result usually accompanies it?

a positive nitrite reaction

25

Positive leukocyte esterase may be found without bacteriuria in what 4 conditions?

1. Trichomonas
2. Chlamydia
3. Yeast infections
4. inflammation of renal tissues

26

What is the specificity of Leukocyte Esterase?

specific for esterase

27

What causes false positive for Leukocyte esterase?

1. Vaginal Contamination
2. Medications that falsely color urine

28

What causes false negatives for Leukocyte esterase?

1. increased glucose >3 g/dl
2. increased protein > 500mg/dL
3. High specific gravity
4. Certain medications

29

Nitrites:
- principle

Greiss Reaction

30

Nitrites:
- clinical significance

Bacteria convert nitrates into nitrites. Nitrites are an abnormal finding

31

Nitrites:
- Indicates the presence of what?

Gram Negative bacteria

32

Nitrite:
- What is it when bacterial infection ascends from the bladder to the ureters and kidneys?

Pyelonephritis

33

Nitrite:
- False Positives

1. Falsely colored urine
2. Improper storage allowing for bacterial proliferation

34

Nitrite:
- False Negatives

1. Ascorbic Acid (vitamin C)
2. The enzyme is only found in gram neg bacteria