Flashcards in Chemistry Deck (46)
What is the function of cystatin C
*Endogenous substances used to determine GFR are urea nitrogen, creatinine and cystatin C
Pt has low serum cholinesterase level--what is next step in workup?
Test if cholinesterase can be inhibited by dubicaine
**In hereditary hypocholinesterasemia, cholinesterase will not be inhibited by dubicaine
Most common drug to cause drug-induced lupus?
Which lipid tests are invalid if patient is not fasting?
triglycerides and calculated LDL
Where is DHEA-S produced?
What type of bilirubin is water insoluble and bound to albumin in blood?
What type of bilirubin is water soluble?
4 diagnostic criteria for DM
OGTT 2 hr >= 200 (75g ora glucose load)
Random plasma glucose >=200
Which patients have macro CK type 1?
healthy elderly women
Which patients have mitochondrial CK (macro-ck type 2)?
What does prealbumin bind in the serum?
thyroxine (aka transthyretin)
retinol binding protein: vitamin A complex
Causes of pseudo M-spike on SPEP?
Fibrinogen (incompletely clotted sample
hemoglobin (hemolyzed sample)
elevated transferrin (beta area)
Medicaitons (antibiotics, radiocontrast agents)
Serum tumor markers (e.g. CA 19-9)
Define type 1 cryoglobulin
monoclonal immune globulin associated with MM or waldenstrom
Define type 2 cryoglobulin
mixture of monoclonal IgM and polyclonal IgG; IgM has rheumatoid factor activity (anti-IgG)
-most common type
Define type 3 cyroglobulin
mix of two polyclonal Ig's, typically IgG and IgM; IgM has rheumatoid factor activity
What is the most common cause of mixed cryoglobulinemia (type 2+3)
Sx include leukocytoclastic vasculitis, arthralgia, LAD hepatosplenomegaly, anemia, sensorineural hearing deficits, MPGN type II
what medical conditions can cause pseudohyponatremia?
(due to decreased water content of plasma)
What cancers can secrete PTHrp?
SCC lung, head and neck, skin ,cervix and esophagus
T cell lymphoma
What forms of PTH are biologically active?
-rapidly cleared from blood T1/2=5 mins
What is cause of increased BUN/creatinine ratio?
normal 10:1, if greater than 20:1 prerenal azotemia (due to hypoperfusion)
Most common cause of false pos b-hCG
Quad screen showing low AFP, low uE, raised hCG and raised DIA
Trisomy 21 (Downs)
Quad screen showing low AFP, hCG and uE
Trisomy 18 (edwards)
Quad screen showing elevated AFP, normal hCG and low uE
What is metabolite of serotonin (5-HT) that is produced by carcinoids?
5 hydroxyindoleacetic acid (5-HIAA)
excreted in urine
What do foregut carcinoids produce?
histamine, catecholamines, 5 hydroxytryptophan (5-HTP)
What do midgut carcinoids produce?
What do hindgut carcinoids produce?
usually nothing! non-secretory
VMA is a metabolite of what
norepi-->normetanephrine-->vanillylmandelic acid (VMA)