Heme-Onc Lab Flashcards
Why are tumor markers tricky?
certain tumor markers can be elevated in multiple types of cancer; tumor markers are not always elevated; tumor markers have not been identified for all cancers
Cancer HPI:
Weight loss, fatigue, night sweats, pain, cough, blood in stool
PET Scan
Injecting someone with radioactive sugar and if it lights up, it means they have Cancer
Tumor markers don’t diagnose a cancer, a _____________ diagnoses a cancer
Pathologist
Sensitivity
% of people who DO have cancer and WILL have an abnormal test
Specificity
% of people withOUT cancer who will have a NEGATIVE test
What are the 5 general categories of tumor markers?
Antigens, Enzymes, Hormones, Oncogenes, Tissue Receptors
What is an antigen?
Protein found in larger amounts during fetal development; sometimes cancer cells will have high levels of fetal antigens
Antigen examples:
AFP, CEA, PSA, Ca-125, Bence Jones Proteins
Malignant tissue might cause the blood to have increased enzymes. How do you measure them? / Examples
Immuneoassay / Prostatic Acid Phosphatase, all ase’s
What are common hormones that indicate cancer?
Beta-HCG, Human Calcitonin
Examples of Oncogenes you could look for
BRCA1, BRCA2, Philadelphia Chromosome
Tissue receptors can be helpful in guiding:
Therapy choices
Most tumor markers are used to monitor:
Recurrence of cancer following treatment
What is AFP?
Antigen: Alpha Fetoprotein; found in fetal GI tract; increased in 80-90% of pts with hepatocellular carcinoma; used to screen patients with cirrhosis/hepatitis
What is Bence Jones Proteins?
Antigen; used to detect and monitor Multiple Myeloma; found in urine; 2-20% don’t produce this
What is HCG?
Hormone. Usually absent except in pregnant women. Presence otherwise is due to germ cell tumors in men or cancer of the uterus
What are BRCA1 and 2?
Oncogenes
What risk do men with BRCA 1 or 2 have?
risk for prostate or breast cancer; can pass mutation on to daughter
What is Ca-19-9?
An ANTIGEN; useful in diagnosing hepatobiliary cancer.
What is CA-125?
ANTIGEN. Elevated in 80-90% of women with ovarian cancer; after 2 cycles of chemo is a good prognostic indicator.
What is CEA?
ANTIGEN: useful in diagnosing GI, colorectal cancers.
What is the PSA antigen?
Antigen for detecting prostate cancer
Sensitivity and specificity of PSA?
High sensitivity, LOW specificity.
Tumor markers generally make _____ screening tests
poor
Tumor markers are helpful for ______________
following a known Ca / evaluating therapy
Surgical Needle Biopsy:
Can be either incisional (take part of the tissue & test it) or Excisional (take all of the suspicious tissue)
Endoscopic Biopsy
Lighted tube w/lens is used to look inside body and take tissue samples
Frozen Section:
Think Moh’s: tissue sections are prepared during surgery. Frozen –> sliced –> stained
Exfoliative cytology:
Scraping scalpel over lesion
TIBC
Total Iron Binding Capacity; measures the extra room transferritin has to shuttle iron around (high TIBC means low iron b/c lots of available iron transport)
Serum Ferritin
Should be higher than your age; best test to get at iron level; ferritin needs iron to be synthesized
MCHC
Mean Corpuscular Hemoglobin Concentration = Hemoglobin / Hematocrit… this number tells you hwo dark the cells are (the darker they are, the more hemoglobin they have in them)… hyper vs hypochromic
HgB Electrophoresis
useful in detecting odd hemoblogin (i.e. in Thalassemia, Sickle Cell Anemia)
Bone Marrow Biopsy
Gold standard in anemia treating, however, VERY expensive
Bilirubin
If this is elevated, it indicates hemolytic anemia b/c cells are breaking apart and dumping their contents into the blood stream
Reticulocyte count in a patient with anemia
you would expect it to be elevated to make up for decreased RBCs… if it is not, then that is a very bad sign!
Where do the intrinsic and extrinsic clotting pathways converge?
At the activation of Factor X
Extrinsic Pathway:
Tissue factor activates Factor VII which activates Factor X
Common pathway
After Factor X is activated, the pathways come together. Common pathway: Factor X activates Factor V which converts prothrombin to thrombin. Thrombin activates fibrinogen to its active state, fibrin.
Which pathway does a PT test?
Extrinsic pathway
You would draw a PT to monitor which med?
Warfarin
What does a prolonged PT mean?
Either a factor 7 defect or Vit K deficiency
A prolonged PT indicates?
Lack of clotting; a problem in the extrinsic clotting cascade.
Which pathway does an INR measure?
Extrinsic
What is an INR a ratio of?
A patient’s PT / Normal mean PT
What pathway does an aPTT test?
Intrinsic
What does an elevated PTT indicate?
Deficiency or inhibition of intrinsic clotting factors
What medication is a PTT used to monitor?
Heparin
What is an FSP?
Fibrin Split Product
What does an elevated FSP mean?
Either excessive activation of thrombin OR excessive degredation of fibrin/fibrinogen.
What can an elevated FSP indicate?
DIC.
What pathway does FSP measure?
Common
What pathway do Factor Assays measure?
Could measure any component of either pathway
When would you run a factor assay?
When you have an elevated PT or PTT and want to isolate why.
What do you use the Direct Coomb’s Test for?
Autoimmune Hemolytic Anemia b/c it measures surface antibodies
When is an Indirect Coomb’s Test done?
pregnancy or before transfusion to ensure hemolytic anemia does not occur
Which pathway does a D-Dimer measure?
Common
What does a D-Dimer measure?
Fiber degradation; it tells us that there was a clot and it is being busted up.
What is different about frozen packed RBCs vs packed RBCs
Frozen is devoid of WBCs and plasma cells
What do you give someone with a low hematocrit or Hgb?
Packed RBCs not whole blood
Autologos RBCs
Patient’s own blood
When can hemolysis occur during a blood transfusion?
If someone is given the wrong type of blood
Leukoagglutinin Reactions
Reaction to antigens on WBCs
What type of blood would you give someone who has experience leukoagglutinin reactions?
leukocyte poor blood or frozen PRBCs
Warfarin works by:
Antagonizes Vitamin K & interferes with synthesis of Vitamin K-dependent clotting factors
Dabigatran works by:
Inhibiting Thrombin (thus preventing cleavage of fibrinogen to fibrin)
Heparin works by binding to:
Antithrombin III; this inhibits factor X and the conversion of fibrinogen to fibrin
Low Molecular Weight Heparin
Lovenox
What are the advantages of LMWH?
in/out pt use, longer half life, greater bioavailability
Heparin can be:
Injected only
List the 3 platelet inhibitors:
Asparin, Ticlopidine, Clopidrogel
How does asparin work?
Inhibits cox-1 and 2 enzymes which inhibit prostaglandins and inhibit platelet aggragation
How do clopidrogel and ticlopidine work?
By blocking ADP receptors and causing a reduction in platelet aggregation
