Exam 10 (Tumor markers, NPNs, Calcium and Bone homeostasis) Flashcards
Which non protein nitrogen is found in greatest concentration in plasma?
Urea nitrogen
Urea is excreted by all of the following, except:
A. GI tract
B. kidneys
C. skin
D. breath
D
How can urea nitrogen be converted to urea concentration?
Multiply by 2.14
Analytical methods for Urea
Urease (most common)
GLDH
Azotemia
Elevated urea in blood
Uremia
Elevated urea in blood WITH renal failure
Causes of prerenal azotemia
CHF, Shock, dehydration (circulation-related)
Causes of renal azotemia
Renal failure, glomerulonephritis
Cause of post-renal azotemia
Obstruction such as tumor or kidney stone
T/F: creatinine remains stable daily
true
What NPN is associated with muscle mass?
Creatinine
What is inversely proportional to GFR?
Creatinine
What are the analytical methods for creatinine?
IDMS
Jaffe reaction
What is the GFR?
Volume of plasma filtered by the glomerulus per unit of time
What is the formula for GFR?
(urine creatinine)(urine volume)/plasma creatinine
Renal clearance substance measurement characteristics
- stable concentration in plasma
- physiologically inert
- freely filtered at the glomerulus
- do not want kidney to secrete/reabsorb/metabolize it
Formula for creatinine clearance
U x V 1.73
______ x _______
P SA patient
What four variables are in the CKD-EPI/MDRD measurement for eGFR?
Serum/plasma creatinine
patient age
patient gender
patient ethnicity
Equations to measure eGFR
Schwartz
MDRD
CKD-EPI
eGFR <15 = ?
Kidney failure
What is the normal BUN/creatinine ratio?
10:1 or 20:1
Clinical applications of uric acid measurement
Detect and monitor kidney disfunction
Detect kidney stone formation
Monitor conditions with increased nucleic acid catabolism (leukemia, lymphoma)
Toxemia of pregnancy (Preeclampsia)
Gout
Analytical methods for uric acid measurement
Uricase
What is the #1 application of ammonia measurement?
Hepatic failure
Why would ammonia levels be measured?
Hepatic failure
Reye’s syndrome
What are the special considerations when handling ammonia samples?
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
Benign vs malignant
Benign = non cancerous, stays at primary site
Malignant = cancerous, has potential to spread to other sites
Metastasis
Spread of cancer to other parts of the body
Apoptosis
Programmed cell death (natural part of normal cell)
Angiogenesis
Creation of blood vessels
Oncogene vs tumor suppressor genes
Oncogene = bad, encodes for uncontrolled cell growth
TSG = good, encode for proteins that suppress tumor cells
Stage I to Stage IV of cancer
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
Characteristics of an ideal tumor marker
- easy to measure, inexpensive, and easily obtained from body fluids
- be specific to a tumor
- have a correlation between measured level and tumor size
- have an abnormal level at early stage
- have stability (do not fluctuate)
- if present in benign conditions, is at much lower level than malignant conditions