Clinical Chemistry Test Questions – Flashcards

Prostate cancer

PSA=protease-->minimize the viscosity of the ejaculate

- minimal

- markedly=> measure before/several weeks after manipulation

processed within 2hrs / freeze

-->less stable than bound PSA

increased pro-PSA and truncated PSA isoforms¹

¹pPSA-->anomalous clipping

weak in first 5yrs post treatment

preop--> PSA ~ tumor volume and stage

Smoking, peptic ulcer dz,IBD,pancreatitis, hypothyroidism, biliary/bowel obstruction, cirrhosis

¹CEA < 10ng/mL

Tumor stage, grade, site (L>R), ploidy

obstruction,liver function (metabolism)

serial CEA measurements

most sensitive--> liver mets

poorly sensitive--> locoregional recurrence

Anti-thyroglobulin Ab's-;10% (nml Indiv.),;20%Pt w thyroid Ca

2. Macro-thyroglobulin

;

Serial quantitative [anti-thyroglobulin Ab]_serum

increase<--Ag stimulation<-- recurrence

Tumor-Associated Trypsin Inhibitor (TATI)

also in pancreatic adenoca-->limited specificity (pancreatitis)

gastric ca (60%) --> diffuse, infiltrative,signet ring

Renal failure

Pancreatitis--> degree of elevation ~ severity

Non-mucinous epithelial ovarian neoplasm

elevated only ~ 50% --> stage I dz

Ovarian malignancy ( epithelial, non-mucinous)

PPV >95%

CA27.29 (more sensitive &specific), CA15-3

--> different epitopes of a single Ag = protein product of breast ca assoc MUC1 gene

benign ovarian cysts, liver dz, benign breast dz

CA 15-3--> sarcoidosis and lupus

IHC: ER, PR, Her-2¹ (c-erb-2) Nc staining % of tm cells

--> correlates well with biochemical assays (ligand binding)

¹IHC & / FISH -->Rx: trastuzumab

IHC:Only membranous staining-->only Inv. component

0-3+ --> 2+ => FISH

CA19-9 >1000¹ U/L

¹not seen in benign dz ( <100 U/L)

 = Lewis blood group Ag

not produced by Le^- people

Major component of fetal serum --> ~ albumin

Yolk sac, fetal liver/GI tract

undetectable-->post partum, adults < 5.4ng/mL

benign conditions < 100 ng/mL

Yolk sac tm--> [AFP] ~ prognosis

HCC -->[AFP] ~ overlap w benign dz

Hepatoid variant of gastric Ca

beta₂-Micoglobulin --> surface-most nucleated cells

-->non-covalent link to MHC I

Increased cell turnover¹ => elevated beta₂M²

¹solid tm & hematolymphoid neoplasms,²renal isufficiency

-->osteoblastic activity (osteogenic sarcoma, bone mets,

active Paget disease of bone)

~ Liver function--> hepatic mets (carcioids~prognosis)

Carcinoid

Foregut: stomach, proximal duodenum and lung

Carcinoid

Midgut: distal duodenum,jejunum,ileum,appendix,right colon

Distal 1/3 of transverse, descending colon,sigmoid colon and rectum

~hCG

Platelet serotonin

--> take up serotonin from the serum @ constant rate

--> not affected by diet (tryptophan rich)

Carcinoid --> 20-30% ~ normal (foregut,hindgut)

False elevation--> tryptophan rich diet

5-HT--> platelets -->some 5-HT--> renal tubules => 5-HIAA

Chromogranin A

Small cell NE, pheo,carcinoid,islet cell tm

MTC

Hashimoto, C-cell hyperplasia, breast ca

2⁰ -->chronic renal failure, Zollinger-Ellison syndrome

provocative testing - pentagastrin/omeprazole/Ca⁺⁺

--> in MEN II families

Pheochromocytoma--> adrenal medulla --> norepinephrine --PNMT-->epinephrine

Extra-adrenal tm --> mainly norepinephrine

Paraganglioma¹/Pheochromocytoma²/ Neuroblastoma³

--> fractionation of catecholamines/metanephrines

¹norepinephrine--> normetanephrine --> VMA

²epinephrine--> metanephrine --> VMA

³also homovanillic acid--> metabolic product of DOPA & dopamine

1.free Metanephrine_plasma

2. Metanephrine/Catecholamine_urine

plasma catecholamines --> poor sensitivity --> episodic release

plasma metanephrines--> long term catecholamine secretion

<-- poorly difeerentiated Neuroblastoma

=> worse prognosis

urinary NMP22--> sensitive,nonspecific (1-6wks post Sx)

Inflammation-->rapid cell turnover --> false +

Leukocytes--> false +

PCA3/DD3

RNA fro urine sediment--> quantitative real time PCR

=> # DD3 RNA transcripts (nontranslated mRNA)

¹Increase leakage into the extracellular matrix

KLK3 gene (encodes PSA) --> not upregulated in Prostate adenoca