Exam 10 (Tumor markers, NPNs, Calcium and Bone homeostasis) Flashcards

1
Q

Which non protein nitrogen is found in greatest concentration in plasma?

A

Urea nitrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Urea is excreted by all of the following, except:
A. GI tract
B. kidneys
C. skin
D. breath

A

D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How can urea nitrogen be converted to urea concentration?

A

Multiply by 2.14

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Analytical methods for Urea

A

Urease (most common)
GLDH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Azotemia

A

Elevated urea in blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Uremia

A

Elevated urea in blood WITH renal failure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Causes of prerenal azotemia

A

CHF, Shock, dehydration (circulation-related)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Causes of renal azotemia

A

Renal failure, glomerulonephritis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Cause of post-renal azotemia

A

Obstruction such as tumor or kidney stone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

T/F: creatinine remains stable daily

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What NPN is associated with muscle mass?

A

Creatinine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is inversely proportional to GFR?

A

Creatinine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the analytical methods for creatinine?

A

IDMS
Jaffe reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the GFR?

A

Volume of plasma filtered by the glomerulus per unit of time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the formula for GFR?

A

(urine creatinine)(urine volume)/plasma creatinine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Renal clearance substance measurement characteristics

A
  1. stable concentration in plasma
  2. physiologically inert
  3. freely filtered at the glomerulus
  4. do not want kidney to secrete/reabsorb/metabolize it
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Formula for creatinine clearance

A

U x V 1.73
______ x _______
P SA patient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What four variables are in the CKD-EPI/MDRD measurement for eGFR?

A

Serum/plasma creatinine
patient age
patient gender
patient ethnicity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Equations to measure eGFR

A

Schwartz
MDRD
CKD-EPI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

eGFR <15 = ?

A

Kidney failure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the normal BUN/creatinine ratio?

A

10:1 or 20:1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Clinical applications of uric acid measurement

A

Detect and monitor kidney disfunction
Detect kidney stone formation
Monitor conditions with increased nucleic acid catabolism (leukemia, lymphoma)
Toxemia of pregnancy (Preeclampsia)
Gout

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Analytical methods for uric acid measurement

A

Uricase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the #1 application of ammonia measurement?

A

Hepatic failure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Why would ammonia levels be measured?

A

Hepatic failure
Reye’s syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are the special considerations when handling ammonia samples?

A

Tube should be full and put on ice immediately after collection since ammonia is very unstable
Should be refrigerator-centrifuged
Hemolysis heavily affects ammonia levels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Benign vs malignant

A

Benign = non cancerous, stays at primary site
Malignant = cancerous, has potential to spread to other sites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Metastasis

A

Spread of cancer to other parts of the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Apoptosis

A

Programmed cell death (natural part of normal cell)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Angiogenesis

A

Creation of blood vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Oncogene vs tumor suppressor genes

A

Oncogene = bad, encodes for uncontrolled cell growth
TSG = good, encode for proteins that suppress tumor cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Stage I to Stage IV of cancer

A

stage 1 = localized primary tumor
stage 2 = invasion of primary tumor through epithelium and into blood vessels
stage 3 = migration of tumor into lymph nodes
stage 4 = metastasis and invasion of tumor into distant tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Characteristics of an ideal tumor marker

A
  1. easy to measure, inexpensive, and easily obtained from body fluids
  2. be specific to a tumor
  3. have a correlation between measured level and tumor size
  4. have an abnormal level at early stage
  5. have stability (do not fluctuate)
  6. if present in benign conditions, is at much lower level than malignant conditions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What will a low cutoff value affect for tumor markers?

A

High sensitivity
Low specificity
False positives

35
Q

What will a high cutoff value affect for tumor markers?

A

Low sensitivity
High specificity
False negatives

36
Q

Sensitivity

A

Ability of assay to detect disease

37
Q

Specificity

A

Ability of assay to classify individuals who do not have the disease

38
Q

PPV

A

Probability of having the disease if test is positive

39
Q

NPV

A

probability of having the disease if test is negative

40
Q

Prevalence

A

frequency of disease in a given population

41
Q

What is the Hook Affect?

A

When there is so much tumor marker present that the response is not accurate; resolve by diluting specimen

42
Q

ACTH

A

elevated levels found in pituitary adenomas and ectopic ACTH-producing tumors

43
Q

Estrogen and progesterone receptors

A

Associated with some types of breast cancer

44
Q

Calcitonin

A

Associated with medullary thyroid cancer

45
Q

hCG

A

Can be produced in trophoblastic tumors, choriocarcinoma, and germ cell tumors of the ovary and testis (preferable to use beta-hCG)

46
Q

AFP

A

Oncofetal antigen
ADP normally elevated in newborns
If elevated in adults = liver cancers, teste cancers, ovarian cancers, hepatitis, cirrhosis

47
Q

CEA

A

Elevated in colorectal, GI, lung, and breast cancer
Can be elevated in smokers

48
Q

CA 15-3 and CA-27.29

A

Associated with breast cancer
Elevated levels seen in 70-80% of metastatic breast cancers
Useful for monitoring, not screening

49
Q

CA 125

A

Detects ovarian cancer

50
Q

What can be run in parallel with CA 125 to improve sensitivity?

A

Transferrin, B2 microglobulin, apolipoprotein, lipase

51
Q

CA 19-9

A

Non-specific, but can be suggestive of pancreatic cancer, lung cancer, colorectal cancer, and hepatobiliary cancer

**Related to Lewis blood group antigen
If Lea and Leb negative, cannot produce CA 19-9

52
Q

Thyroglobulin

A

Elevated levels associated with thyroid cancer

53
Q

Chromogranin A

A

Released from adrenal medulla
Elevated in patients with neuroendocrine tumors

54
Q

PSA

A

Only tumor marker currently FDA approved for screening for disease
Can also be elevated in benign prostatic hyperplasia and prostatitis (NOT specific to only prostate cancer)

55
Q

PSA levels and their associations with prostate cancer/benign prostatic hyperplasia

A

PSA <4 is normal
PSA 4-10 could be BPH
PSA >10 associated with prostate cancer 67% of the time
PSA >50 associated with prostate cancer 99% of the time

56
Q

Osteoblasts vs osteoclasts

A

Osteoblasts = build bone
Osteoclasts = break bone down

57
Q

If blood calcium levels are decreased, what will PTH do?

A

Increase

58
Q

If blood calcium levels are increased, what will PTH do?

A

Decrease

59
Q

How do PTH affect calcium

A

Inc PTH = Inc calcium

60
Q

What is the most important test in differential diagnosis of hypercalcemia?

A

PTH

61
Q

2 causes of hypercalcemia related to PTH

A
  1. Primary hyperparathyroidism
  2. hypercalcemia-associated malignancy
62
Q

What is the most common cause of hypocalcemia?

A

Chronic renal failure

63
Q

Pseudohypoparathyroidism

A

Increased PTH

64
Q

Active metabolite of Vitamin D

A

1,25 (OH)2 AKA calcitriol - made in kidneys only

65
Q

What is the form of vitamin D that is measured in the lab?

A

25(OH)

66
Q

Increased PTH with decreased phosphate = ? vitamin D

A

Increased

67
Q

Decreased calcium and Increased PTH = ? vitamin D

A

Increased

68
Q

How much calcium is ionized? aka free

A

50%

69
Q

How much calcium is bound to proteins?

A

40%

70
Q

How much calcium is complexed with small anions?

A

10%

71
Q

Causes of hypocalcemia

A

Hypoparathyroidism
Vitamin D deficiency
Hypomagnesemia
Chronic renal failure
Hypoalbuminemia

72
Q

S&S of hypercalcemia

A

Lethargy
Decreased alertness
Depression

73
Q

S&S of hypocalcemia

A

tetany
numbness
tingling

74
Q

Most common cause of hypercalcemia in outpatients?

A

Primary hyperparathyroidism

75
Q

Most common cause of hypercalcemia in inpatients?

A

Malignancy

76
Q

What medications can cause hypercalcemia?

A

Lithium
Thiazide diuretics
High doses of vitamin A
high doses of vitamin D
Milk-alkali syndrome

77
Q

What can be measured with hepatitis C antibody to help tell us how long the patient has been infected?

A

HCV RNA and ALT

78
Q

What does Hep C antibody tell us?

A

Tells us patient has been infected before, but not specific for acute/chronic or if they are currently infected or not

79
Q

What substances can be used to measure renal clearance?

A

Inulin, Cystatin C, Creatinine

80
Q

Pros/cons of Inulin as a measurement of renal clearance

A

Pros: exogenous (not normally found in body)
Cons: IV injection to administer, do not have widely available measurement techniques in the lab

81
Q

Pros/cons of cystatin C as a measurement of renal clearance

A

Pros: LMW protein, easy to use, levels unaffected by gender/diet/muscle mass
Cons: Concentrations can be affected by thyroid disease, most labs do not have methods

82
Q

Pros/cons of Creatinine as a measurement of renal clearance

A

Pros: automated methods available, can use serum, plasma, or urine

83
Q

What is the most common method used to measure renal clearance? Is it the best method?

A

Creatinine. It is not the best method, but the most common one that is available.