Proteins Flashcards
What is the most abundant serum protein?
Albumin
What are the manifestations of Analbuminemia?
- Mild Edema
- Hyperlipidemia
Clinical utility of measuring Albumin? (5)
- Nutritonal status
- Hepatic synthetic function
- Renal glomerular function
- Negative acute phase reactant
- Diabetic control
What is the T1/2 of albumin?
17 days
What is glycated albumin an indicator of?
short term glycemic control
Function of Prealbumin.
- Binds thyroxine (transthyretin [TTR])
- Binds aRetinol binding protein (Vit.A complex)
Clinical utility of measuring Prealbumin? (3)
- Nutritional status
- Negative acute phase reactant
- Hallmark of CSF protein electrophoresis
What is the major component of the alpha1 band?
-Alpha1-Antitrypsin (AAT)
Alpha1-Antitrypsin (AAT):
- Gene
- # of alleles
- MC allele
- MC genotype
- SERPINA1
- > 100 alleles (Polypmorphic)
- PiM (MC allele)
- PiMM (MC genotype)
Genotype for AAT deficiency?
PiZZ
What is the major component of increased alpha1 ban in acute inflammatory states?
Alpha1-Glyocoprotein
*Normally only a minor component of a1 band
Relative concentrations of a2-macroglobulin is elevated in what conditions?
-Liver and Kidney disease
T/F: a2-macroglobulin is lost in nephrotic syndrome.
False
-large size prevents loss, leading to a relative 10 fold rise in concentation
Ceruloplasmin is involved in what disease?
Wilson’s Disease
-Decreased levels
what is the 3rd major component of the a2 band?
Haptoglobin
What is the role of Haptoglobin?
Binds free Hb
-Rapidly depleted in Intravascular Hemolysis
What is the major Beta Globulin?
Transferrin
Function of Transferrin.
Transports Ferric (Fe3+)
Transferrin levels in IDA.
Markedly INcreased
*normally ~30% Saturated
Transferrin:
-Hallmarks of CSF electrophoresis
- Asialated transferrin (so called tau protein)
- Double transferrin peak
What is a beta-globulin that is usually absent from serum?
Fibrinogen
When might you see Fibrinogen on electrophoresis?
If specimen clots incompletely
- May produce psuedo M spike
- May straddle beta/gamma interface
Where is C reactive protein (CRP) found on SPEP?
-gamma region
What is a normal CRP value?
<3 mg/L
What is a HIGH level CRP elevation, and what may it indicate?
> 10 mg/L
-Active inflammation
What is a LOW level CRP elevation, and what may it indicate?
3-10 mg/L
- Cellular stress
- Correlated with higher all cause mortality
- Poor outcome following CV events
Normal SPEP pattern.
- Large albumin band (prealbumin invisible)
- small peaked a1 band
- broad a2 band
- bimodal beta
- broad gamma
Bisalbuminemai SPEP pattern.
Double albumin spike
- Heterozygotes for albumin alleles
- Insignificant
AAT deficiency pattern.
Absent A1 band
-not the most sensitive or specific assay
Nephrotic syndrome SPEP pattern.
Decrease of ALL bands
-EXCEPT a2 band that contains a2-macroglobulin
*loss of small serum proteins, particularly Albumin
Acute inflammation SPEP pattern.
- Decreased Albumin
- Increased a1 and a2 bands
- normal to increased gamma band
When is Beta-gamma bridging seen?
- Cirrhosis
- Increased serum IgA
What are additional features seen in beta-gamma bridging?
- Hypoalbuminemia
- Blunted a1 and a2 bands
M spike is most commonly due to what conditions? (3)
- Plasma cell neoplasm
- Waldenstrom (lymphoplasmacytic lymphoma)
- CLL/SLL
What causes a pseudo M spike? (6)
- Fibrinogen (incompletely clotted)
- Hemoglobin (hemolyzed)
- CRP Increase
- Transferrin Increase
- Abx/contrast dyes
- Tumor markers
Where are most IgG paraproteins found in SPEP?
gamma region
Where are most IgM paraproteins found in SPEP?
beta-gamma interface
Where are most IgA paraproteins found in SPEP?
beta region
T/F: CSF normally contains essentially all proteins present in serum.
True; although smaller quantities
What are the characteristic features of CSF on PEP?
- Prominent Prealbumin band
- Double beta (transferrin) band
Findings of CSF electrophoresis in MS?
Oligoclonal bands
-should be Absent from serum
Urine Electrophoresis:
-Glomerular proteinuria
- Strong Albumin
- Strong a1
- Strong Beta
*Intermediate sized proteins - Albumin, AAT, transferrin
Urine Electrophoresis:
- Tubular proteinuria
- Weak Albumin
- Strong a1
- Strong Beta
Urine Electrophoresis:
- Overflow proteinuria
- Monoclonal light chain (Bence Jones)
- Absent albumin, a1, a2, beta (decreased)
Definition of cyroglobulins.
Immunoglobulins that precipitate reversibly at low temperature.
Steps for detecting cyroglobulins.
- 37 till clotted
- centrifuge at 37
- Serum placed at 4 for >3 days
- centrifuge at 4
- precipitate is cryoglobulin
- characterized by electrophoresis or immunofixation
What are type I cryoglobulins?
-Monoclonal Igs ass. w/ MM or Waldenstrom
What are type II cryoglobulins?
- Mixture of a monoclonal IgM and Polyclonal IgG
- IgM has rheumatoid factor activity (anti IgG)
What are type III cryoglobulins?
- Mixture of 2 polyclonal Igs (typically IgG and IgM)
- IgM has rheumatoid factor activity
What is the most common type of cryoglobin?
Type II
What is the MCC of mixed cryoglobinemia (types II and III)
HCV infection
what is the pH for Electrophoresis of serum? How are the bands measures?
- 8.6
- Densitometry
