Clinical Chemistry I Exam 3

Front 1

Characteristics of an ideal marker for renal clearance

Back 1

stable concentration in plasma

freely filtered at the glomerulus

not reabsorbed, secreted, synthesized or metabolized by the kidney

Can be easily measured using colorimetric assays

Amount filtered at the glomerulus is the amount excreted in the urine

Front 2

Clearance calculation

Back 2

urine concentration x urine volume = plasma concentration x blood flow (glomerular filtration rate)

Front 3

Uncorrected GFR =

Back 3

UV/P (with normal renal function)

Front 4

Corrected GFR =

Back 4

UV/P x 1.73m^2/BSA

Front 5

Inulin is a ________ not normally present in the body. Inulin clearance is the gold standard for assessment of ______. However, this method is not very ________.

Back 5

fructo-polysaccharide/artificial carbohydrate, GFR, specific

Front 6

Creatinine clearance is overestimated by _____ due to the ______ of creatinine by the kidney.

Back 6

10%, secretion

Front 7

Creatinine clearance requires what sample(s)?

Back 7

24 urine collection, serum/plasma collected concurrently

Front 8

Reference ranges for creatinine clearance

Back 8

males: 97 to 137 mL/min/1.73m^2

females: 88 to 128 mL/min/1.73m^2

Front 9

GFR and creatinine clearance decrease with

Back 9

Decreased renal plasma flow, clogged basement membrane, chronic renal disease, age

Front 10

Estimated GFR equation

Back 10

GFR = (140-age x weight (kg))/(72 x P) x K

k = 0.85 for women, 1.0 for men

Front 11

Estimated GFR does not require ________.

Back 11

timed urine collection

Front 12

Estimated GFR is helpful in early detection of _________ because serum creatinine will not be abnormal until ______.

Back 12

chronic kidney disease, 50% of renal function is lost

Front 13

Non-protein nitrogen compounds are used to ____________.

Back 13

monitor and assess renal function

Front 14

Non-protein nitrogen compounds arise from the breakdown of proteins and nucleic acids and include:

Back 14

urea, creatinine, creatine, uric acid, ammonia, amino acids

Front 15

Define azotemia

Back 15

elevated level of NPN compounds in blood

Front 16

The normal BUN to creatinine ratio is _______.

Back 16

10:1-20:1.

Front 17

Urea is synthesized in the ______ from _____ and _____ arising from the deamination of amino acids.

Back 17

liver, CO2, ammonia

Front 18

40-60% of urea is ________ by the kidneys. The rest is ______.

Back 18

reabsorbed, excreted

Front 19

Measurement of urea alone (is/is not) a useful indicator of renal function

Back 19

Is not, urea is highly impacted by hydration status

Front 20

First step in all urea analytic methods

Back 20

urea + 2H2O -----urease-----> 2NH4+ + HCO3-

Front 21

______ and _____ inhibit urease.

Back 21

Citrate and fluoride

Front 22

Endogenous ammonia interferes with urea measurement (T/F)

Back 22

True, endogenous ammonia will cause a falsely increased urea result

Front 23

Reference range BUN

Back 23

6-20 mg/dL

Front 24

Define uremia

Back 24

very high plasma urea concentration accompanied by renal failure

Front 25

Prerenal azotemia is caused by _________.

Back 25

decreased renal blood flow (CHF, dehydration)

Front 26

Renal azotemia is caused by _________.

Back 26

intrinsic renal failure leading to decreased renal function

Front 27

Post renal azotemia is caused by _________.

Back 27

obstruction in the urinary system

Front 28

Decreased urea concentration may be caused by:

Back 28

decreased protein intake, liver disease, severe diarrhea/vomiting, pregnancy

Front 29

Uric acid is synthesized in the ______ from the breakdown of _______.

Back 29

liver, nucleic acids

Front 30

In the kidney, most uric acid is _____. Some uric acid is ____ by the renal tubules.

Back 30

reabsorbed, secreted

Front 31

Most uric acid in plasma is present as _______

Back 31

monosodium urate

Front 32

Reference range for uric acid

Back 32

3.5-7.2 mg/dL male
2.6-6.0 mg/dL female

Front 33

At concentration >6.4 mg/dL, plasma is saturate with urate crystals and the crystals may _________.

Back 33

precipitate in tissues

Front 34

Hyperuricemia is caused by ______ or _______ of uric acid. Overproduction is a result of increased _________ or a _________ diet. Underexcretion is a result of ________.

Back 34

overproduction, underexcretion, catabolism of nucleic acids, purine-rich, renal disease

Front 35

Sample of choice for uric acid measurement

Back 35

serum, plasma, urine

Front 36

Gout occurs when uric acid is so elevated that it ___________.

Back 36

precipitates out of solution in plasma.

Front 37

Gout is caused by:

Back 37

overproduction of uric acid, purine rich diet, drugs or alcohol

Front 38

Gout occurs primarily in:

Back 38

men between 30 and 50 years of age

Front 39

Gouty arthritis is due to

Back 39

MSU crystals in joints and soft tissue causing pain and inflammation

Front 40

Ammonia is formed in the ______ by the deamination of _____.

Back 40

GI tract, amino acids

Front 41

Ammonia is normally metabolized by the ______ to form ______.

Back 41

liver, urea

Front 42

At physiologic pH most ammonia in blood exists as ______.

Back 42

NH4+

Front 43

With an increase in plasma pH, ammonia is converted to the ______ form. This form crosses the ________ more readily and can be _____.

Back 43

NH3, blood-brain barrier, toxic

Front 44

Increased blood ammonia levels are associated with:

Back 44

severe liver disease, Reye's syndrome, renal disease, inherited deficiency of the urea cycle enzymes

Front 45

Reye's syndrome is usually preceded by a _________ infection, after which a child is treated with _______.

Back 45

viral, aspirin

Front 46

Renal disease results in an increased blood ammonia level because _________. However blood ammonia is not a good test for renal disease.

Back 46

BUN increases and more diffuses into the GI tract where it is converted to ammonia

Front 47

Sample of choice for ammonia measurement

Back 47

whole blood or plasma (EDTA or heparin), immediately on ice and centrifuged in a refrigerated centrifuge

Front 48

Sources of error for ammonia measurement

Back 48

hemolysis

drugs

cigarette smoking by patient

ammonia in detergents, reagents, water, glassware

Front 49

Define Cystatin C

Back 49

low molecular weight cysteine protease inhibitor protein produced by all nucleated cells

Front 50

Cystatin C is catabolized by the ________.

Back 50

proximal convoluted tubule

Front 51

Increased serum cystatin C indicates ________.

Back 51

impaired renal function

Front 52

Cystatin C (is/is not) an acute phase reactant

Back 52

is not

Front 53

Cystatin C is produced and removed from the body at a _____ rate.

Back 53

constant

Front 54

A rise in serum cystatin C is measurable before increase in ______ or decrease in ______.

Back 54

creatinine, GFR

Front 55

Serum cystatin C does not depend on _________.

Back 55

age, muscle mass, etc.

Front 56

Commonly used kidney function test

Back 56

creatinine, BUN, creatinine clearance, total protein, uric acid, cystatin C, osmolality, electrolytes

Front 57

Define acute renal failure.

GFR may be reduced to ______.

Back 57

sudden, sharp decline in renal function as a result of acute toxic or hypoxic insult to the kidneys.

<10 mL/min

Front 58

Chronic renal failure occurs in the following ____ stages:

Back 58

5

Kidney damage with normal GFR

kidney damage with normal or decreased GFR

Moderately decreased GFR

Severely decreased GFR

Kidney failure

Front 59

Symptoms of end stage renal disease

Back 59

weakness, tremors, loss of appetite, metabolic acidosis

Front 60

Lab findings in end stage renal disease

Back 60

increased BUN and serum creatinine, decreased GFR, increased serum phosphorus/potassium, decreased serum calcium, increased blood pressure

Front 61

End stage renal disease is reversible (T/F)

Back 61

False, end stage renal disease is irreversible

Front 62

Acute glomerulonephritis (acute nephritic syndrome)

Back 62

injury to glomerular tissue by immune complexes from beta-hemolytic strep infection

Front 63

Lab findings of acute glomerulonephritis

Back 63

hematuria, proteinuria, reduced GFR, increased sodium, hypertension

Front 64

Chronic glomerulonephritis

Back 64

Loss of nephron mass over a prolonged period of time

Front 65

Lab findings of chronic glomerulonephritis

Back 65

reduced GFR, increased sodium, hypertension, slight hematuria, slight proteinuria

Front 66

Nephrotic syndrome

Back 66

increased permeability of the glomerular basement membrane induced by disorders like diabetes mellitus, lupus, etc.

Front 67

Lab findings of nephrotic syndrome

Back 67

hyperproteinuria, hypoproteinemia, azotemia, hyperlipidemia, lipiduria

Front 68

Key symptom of nephrotic syndrome

Back 68

Edema

Front 69

Tubular disease is the result of ________.

Back 69

acute and noninfectious pyelonephritis

Front 70

Tubular disease results in _______.

Back 70

decreased excretion/reabsorption of certain substances or reduced urinary concentrating ability

Front 71

Tubular disease lab findings

Back 71

decreased GFR, acidosis (decreased H+ secretion)

Front 72

Which is more protein rich, interstitial fluid or plasma?

Back 72

Plasma

Front 73

Reference range for plasma sodium

Back 73

136-145 mmol/L

Front 74

Reference range for potassium

Back 74

3.5-5.1 mmol/L

Front 75

Reference range for chloride

Back 75

98-107 mmol/L

Front 76

Reference range for carbon dioxide

Back 76

23-29 mmol/L

Front 77

4 principle plasma electrolytes

Back 77

sodium, potassium, chloride, carbon dioxide

Front 78

Major role of sodium

Back 78

maintaining osmotic pressure due to high concentration in extracellular fluid

Front 79

______ is the major counter-ion available when metabolically produced acids become neutralized to produce their conjugated bases

Back 79

Sodium

Front 80

Sodium serves vital functions in _____, _______ and _________.

Back 80

membrane potential, muscle contraction, nerve conduction

Front 81

Define current

Back 81

rate of flow of electrons measured in amperes

Front 82

Alternating current

Back 82

bidirectional flow of electrons in a circuit first in one direction and then another

Front 83

Direct current

Back 83

unidirectional flow of electrons in a circuit

Front 84

Define electromotive force

Back 84

the force of electron flow measured in volts

Front 85

Ohm's law

Back 85

E = I x R

(Voltage = Current x Resistance)

Front 86

Define resistance

Back 86

ability to stop flow of electrons

Front 87

Coulometry measures the concentration of a substance by measuring ________.

Back 87

the amount of charge involved.

Front 88

Define amperometry

Back 88

A method which measures the concentration of a substance by measuring the amount of current produced by oxidation or reduction of a substance at an electrode

Front 89

Examples of types of amperometry

Back 89

Coulometry, Conductivity, Polarography

Front 90

Polarography determines the concentration by measuring the ______ produced from a polarized electrode where _____ or ______ occurs.

Back 90

current, oxidation, reduction

Front 91

The Clark electrode has what type of membrane?

Back 91

Gas permeable

Front 92

Conductivity is the ability of a solution of electrolytes to carry a ______ between two non-polarized electrodes by migration of ions in a _______.

Back 92

current, potential gradient

Front 93

Potentiometry is the measurement of _______ between two electrodes in a solution.

Back 93

potential (voltage)

Front 94

Potentiometry uses two electrodes: the _____ electrode and the ______ electrode.

Back 94

reference, measuring

Front 95

The concentration of an ion in solution is calculated via difference between reference and indicator electrode in what method of electrochemistry?

Back 95

Potentiometry

Front 96

The Nernst equation describes:

Back 96

the electromotive force generated by H+ at the glass tip of a pH electrode

Front 97

What are ion selective electrodes?

Back 97

Membrane-based electrochemical transducers capable of responding to a specific ion

Front 98

Advantages of ion selective electrodes

Back 98

No standard curve necessary, direct measurement, fast analysis, cost effective (reuse), precise measurements, very sensitive, automation friendly

Front 99

ISE's used to measure sodium incorporate a _______ membrane that is permeable to sodium ions.

Back 99

silicate glass

Front 100

A glass membrane is an ionophore that acts as an ion-exchange resion that changes _______ when the sample's ion replaces the native ion in the resin.

Back 100

voltage

Front 101

Osmotic pressure can be measured by measuring _______ or _______.

Back 101

freezing point depression, decrease in vapor pressure

Front 102

Each _______ of solute depresses the freezing point of H2O by 1.86 degrees celsius

Back 102

1000 mOsm/kg

Front 103

Decrease in freezing point is proportional to _______

Back 103

number of dissolved solute particles present.

Front 104

The 4 major functions of water in the human body

Back 104

transport nutrients to cells, determine cell volume, remove waste by urine, coolant by sweating

Front 105

Which electrolyte is predominant in intracellular fluid?

Back 105

Potassium

Front 106

Which electrolytes are predominant in extracellular environments?

Back 106

Sodium, Chloride

Front 107

Normal plasma is 93% water, the rest is ____ and _____

Back 107

lipid, protein

Front 108

Reference range for sodium

Back 108

136-145 mmol/L

Front 109

Reference range for potassium

Back 109

3.5-5.1 mmol/L

Front 110

Reference range for chloride

Back 110

98-107 mmol/L

Front 111

Reference range for carbon dioxide

Back 111

23-29 mmol/L

Front 112

Sodium plays a major role in maintaining osmotic pressure due to ___________.

Back 112

its high concentration in extracellular fluids

Front 113

Sodium balance is maintained in which two areas of the kidney?

Back 113

Proximal convoluted tubule, distal convoluted tubule

Front 114

Aldosterone maintains sodium levels by acting on the _________ in the kidney.

Back 114

distal convoluted tubule

Front 115

________ maintains cardiac rhythm and contributes to neuromuscular conduction.

Back 115

Potassium

Front 116

Imbalances in _______ level will cause cardiac arrhythmias and neuromuscular weakness.

Back 116

potassium

Front 117

______ is the major intracellular cation

Back 117

Potassium

Front 118

Potassium levels in the body are controlled by the __________.

Back 118

Na-K-ATPase pump

Front 119

Potential causes of hyperkalemia

Back 119

decreased renal function, response to electrolyte imbalance (i.e. acidosis, artefactual (i.e. hemolysis)

Front 120

Potential causes of hypokalemia

Back 120

GI loss (vomiting/diarrhea), renal (i.e. hyperaldosteronism), response to electrolyte imbalance (i.e. alkalosis)

Front 121

Chloride is a major anion found mostly ______ the cellular compartment

Back 121

outside

Front 122

Chloride contributes to the maintenance of acid-base balance by participating in the _______ shift.

Back 122

isohydric

Front 123

Causes of hyperchloremia

Back 123

Loss of bicarbonate, sweating, burns, severe watery diarrhea

Front 124

Hypochloremia

Back 124

Vomiting, following hyponatermia

Front 125

Bicarbonate is reabsorbed in the _____ and ______ in the kidneys

Back 125

proximal convoluted tubule and distal convoluted tubule

Front 126

Increased bicarbonate is associated with what metabolic pH change?

Back 126

alkalosis

Front 127

Decreased bicarbonate is associated with what metabolic pH change?

Back 127

acidosis

Front 128

Equation for anion gap

Back 128

[Na + K] - [Cl + HCO3]

Front 129

Reference range for anion gap

Back 129

10-20 mmol/L if calculated by [Na + K] - [Cl + HCO3]

7-14 mmol/L if calculated by [Na] - [Cl + HCO3]

Front 130

Causes of increased anion gap

Back 130

metabolic acidosis, abnormal concentration of sodium

Front 131

Why does increased potassium usually not result in increased anion gap?

Back 131

Highly increased potassium is not compatible with life

Front 132

Chloride does not usually alter anion gap because __________

Back 132

it crosses the cell membrane easily and never accumulates or gets used up in reactions

Front 133

Define osmosis

Back 133

the diffusion of a liquid through a semi-permeable membrane from low solute concentration to high solute concentration

Front 134

Osmotic pressure is generated by:

Back 134

the presence of more solute on one side of a semi-permeable membrane

Front 135

Osmolality measures:

Back 135

the number of dissolved particles in a solution

Front 136

Osmolality is expressed in:

Back 136

milliosmoles per kilogram of water

Front 137

List the major molecules that contribute to serum osmolality

Back 137

Sodium, chloride, glucose, urea

Front 138

Reference range for plasma osmolality

Back 138

275 to 300 mOsm/Kg

Front 139

Reference range for urine osmolality

Back 139

300-900 mOsm/Kg

Front 140

Equation for estimating plasma osmolality

Back 140

1.86(Na) + (glucose/18) + (BUN/2.8) + 9

Front 141

Each 1000 mOsm/Kg of solute depresses the freezing point of water by _______ degrees celsius.

Back 141

1.86

Front 142

Osmotic pressure can be measure by _____ or _____.

Back 142

freezing point depression, decrease in vapor pressure

Front 143

Osmolal gap detects and measures abnormal concentration of osmotically active solutes other than ___________.

Back 143

sodium, urea and glucose

Front 144

Osmolal gap =

Back 144

measured osmolality - calculated osmolality

Front 145

Body's response to increased osmolality

Back 145

increased thirst (increased water consumption decreases osmolality)

secretion of antidiuretic hormone (increases water reabsorption)

Front 146

Two major hormones that control blood volume

Back 146

Antidiuretic hormone, aldosterone

Front 147

Two major hormones that regulate blood pressure

Back 147

epinephrine, norepinephrine

Front 148

ADH is synthesized in the ______ and stored in the _______.

Back 148

hypothalamus, posterior pituitary

Front 149

The release of ADH is stimulated by _____ circulating around the posterior pituitary

Back 149

hypertonic plasma

Front 150

ADH operates mostly in the _______ of the kidney to increase ________.

Back 150

collecting duct, water reabsorption

Front 151

Epinephrine and norepinephrine are both _______ (modified amines)

Back 151

catecholamines

Front 152

Stimulus for epinephrine or norepinephrine release

Back 152

Nerve impulse from the sympathetic nervous system due to physiological or psychological threat

Front 153

The cause of primary hypertension is _______.

Back 153

unknown

Front 154

What malignancy causes increased secretion of epinephrine/norepinephrine?

Back 154

Pheochromacytoma

Front 155

Hyperaldosteronism due to a tumor leads to _____ blood volume and ____ blood pressure

Back 155

increased, increased

Front 156

Syndrome of inappropriate ADH results in _______ and ______. In this syndrome ____ is inappropriately dilute and _____ is inappropriately concentrated

Back 156

increased blood volume, increased blood pressure, serum, urine

Front 157

Diabetes insipidus is a lack of secretion of or kidney response to _______.

Back 157

Antidiuretic hormone

Front 158

Diabetes insipidus results in a(n) [increase or decrease] of urine volume

Back 158

increase

Front 159

Diabetes insipidus results in low blood pressure (T/F)

Back 159

False, other mechanisms compensate for the loss of fluid

Front 160

Episodic hypertension may occur due to ____ production by intestinal tumors.

Back 160

serotonin

Front 161

Serotonin production by intestinal tumors may be measured by ________.

Back 161

urinary metabolite 5-HIAA

Front 162

Define current

Back 162

rate of flow of electrons measured in amps

Front 163

A typical source for direct current

Back 163

chemical reaction cell such as a battery

Front 164

A typical source for alternating current

Back 164

generators, such as power from an outlet

Front 165

State Ohm's law in words

Back 165

Electromotive force (voltage) depends on the flow of electrons (current) and resistance (ohms)

Front 166

Define resistance

Back 166

The ability to stop flow of electrons

Front 167

Define amperometry

Back 167

A method which measures the concentration of a substance by measuring the amount of current produced by oxidation or reduction of a substance at an electrode

Front 168

The Clark pO2 electrode uses what method of electrochemical analysis?

Back 168

Amperometry

Front 169

Coulometry is what type of electrochemical method?

Back 169

Amperometry

Front 170

Coulometry measures the concentration of a substance by measuring the amount of ______ involved.

Back 170

charge

Front 171

In coulometry, the amount of electricity is directly proportional to the amount of substance produced or consumed by the _______ process at the electrodes

Back 171

redox

Front 172

In the coulometric-amperometric method of chloride measurement, _______ relates to chloride activity

Back 172

time of titration

Front 173

Polarography determines the concentration of an analyte by measuring the current produced from a _________ where oxidation and reduction occurs.

Back 173

polarized electrode

Front 174

The Clark electrode measures ______ by _______ which is a type of amperometry.

Back 174

pO2, polarography

Front 175

Define antigen

Back 175

A substance that can elicit an immune response when injected into a subject

Front 176

Define antibody

Back 176

An immunoglobulin that is formed in response to a foreign substance

Front 177

Define antibody-binding site

Back 177

Part of the antibody that makes contact with the antigen during antigen-antibody reaction

Front 178

Antigenic determinant

Back 178

Portion of the antigen that combines with the binding site of the antibody

Front 179

Define electrostatic force

Back 179

attraction of a positively charged molecule for a negatively charged molecule

Front 180

Electrostatic force is influenced by:

Back 180

ionic state of each molecule, complementary nature of the charges, strength of attraction, distance

Front 181

Define hydrogen bonding

Back 181

Attractive interaction of a hydrogen atom with an electronegative atom that comes from another molecule. The hydrogen must be covalently bonded to another electronegative atom to create the bond.

Front 182

Hydrogen bonding occurs best at ______ temperatures

Back 182

lower

Front 183

Define hydrophobic force

Back 183

the attraction between nonpolar groups

Front 184

Define Van der Waals Force

Back 184

a weak attractive force between the electron cloud of one atom and the nucleus of another molecule

Front 185

Define the law of mass action

Back 185

Binding is dependent on the rate of diffusion and the probability that collision between two molecules will result in binding (this is reversible)

Front 186

Describe the type of binding that occurs between antigens and antibodies in immunoassays

Back 186

highly specific, noncovalent, tight, reversible, forms a complex

Front 187

Immunoassays are useful with the concentration of an analyte is _______

Back 187

low

Front 188

Immunoassays use what type of antibody? This makes them _____.

Back 188

monoclonal, specific

Front 189

Reagent antibodies are produced by ________.

Back 189

injecting animals with the antigen or analytical target

Front 190

Desired properties of immunochemical labels

Back 190

easily attached to antigen/antibody, easily measured, does not interfere with antibody/antigen reaction, inexpensive, stable, non-toxic

Front 191

Define immunochemical label

Back 191

reagent component capable of producing a measureable response that can be attached to an antigen, antibody or binding substrate

Front 192

Types of immunochemical labels:

Back 192

chemiluminescent labels, radioactive labels, enzyme labels, fluorescent labels

Front 193

In competitive immunoassays, the amount of antigen in the sample is ______ related to the amount of label measured

Back 193

inversely

Front 194

In sequential competitive immunoassays, the ______ is added to the antibody first, followed by the ______.

Back 194

unlabeled antigen, labeled antigen

Front 195

Describe the Hook effect

Back 195

immunoassays tend to give falsely low results with the serum concentration of the analyte rises above a certain level

Front 196

What causes the Hook effect?

Back 196

Excess patient antigen saturates both the capture and labeled antibody, resulting in almost no complex formation

Front 197

Heterogenous immunoassays do not required the separation of bound and free labeled antigen or antibody (T/F)

Back 197

False, heterogenous assays DO require separation