Biochemical Testing

Question 0

Which method only measures the number of particles in solution?

Answer 0

Osmolality

Question 1

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

Answer 1

passive transport

Question 2

How should you store reagent strips?

Answer 2

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

Question 3

When should QC be performed on the reagent strips?

Answer 3

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

Question 4

What is the normal for Specific Gravity?

Answer 4

1.003 to 1.030

Question 5

Urine with a specific gravity of 1.010

Answer 5

Isosthenuria

Question 6

Urine with a specific gravity of < 1.010

Answer 6

Hyposthenuric

Question 7

What is the most common cause of Hyposthenuria?

Answer 7

diabetes insipidus or renal disease

Question 8

Urine with a specific gravity >1.010

Answer 8

Hypersthenuric

Question 9

Limitation of specific gravity

Answer 9

only determines specific gravity from 1.000-1.030 in 0.005 increments

Question 10

What lowers specific gravity readings?

Answer 10

highly buffered alkaline urine

Question 11

How do you correct for alkaline urine?

Answer 11

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

Question 12

Principle of pH

Answer 12

Double indicator of Methyl Red and Bromthymol Blue

Question 13

Reference range for pH

Answer 13

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

Question 14

When is acidic urine common during the day?

Answer 14

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

Question 15

WHen is urine suspicious of tampering as far as pH?

Answer 15

below 5 is suspicious

Question 16

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

Answer 16

acidic urine

Question 17

Vegetarian diet leads to what type of pH in urine

Answer 17

alkaline urine

Question 18

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

Answer 18

Alkaline Tide

Question 19

What leads to ACIDIC blood and ALKALINE urine?

Answer 19

Renal tubular acidosis

Question 20

what cells contain leukocyte esterase?

Answer 20

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

Question 21

Leukocyte Esterase Principle

Answer 21

Indoxylcarbonic acid ester > leukocyte esterase > indoxyl

indoxyl + diazonium salt >purple azodye

Question 22

Leukocyte Esterase is associated with what infections?

Answer 22

Bacterial infections or Trichomonas infections

Question 23

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

Answer 23

a positive nitrite reaction

Question 25

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

Answer 25

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

Question 26

What is the specificity of Leukocyte Esterase?

Answer 26

specific for esterase

Question 27

What causes false positive for Leukocyte esterase?

Answer 27

1. Vaginal Contamination

2. Medications that falsely color urine

Question 28

What causes false negatives for Leukocyte esterase?

Answer 28

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

Question 29

Nitrites:

- principle

Answer 29

Greiss Reaction

Question 30

Nitrites:

- clinical significance

Answer 30

Bacteria convert nitrates into nitrites. Nitrites are an abnormal finding

Question 31

Nitrites:

- Indicates the presence of what?

Answer 31

Gram Negative bacteria

Question 32

Nitrite:

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

Answer 32

Pyelonephritis

Question 33

Nitrite:

- False Positives

Answer 33

1. Falsely colored urine

2. Improper storage allowing for bacterial proliferation

Question 34

Nitrite:

- False Negatives

Answer 34

1. Ascorbic Acid (vitamin C)

2. The enzyme is only found in gram neg bacteria