Gc Globulin Elisa Kit                     Price : 440 EURO

To aid the diagnosis of organ damage and the

prognosis of critically ill patients, especially those with

hepatic necrosis including hepatic necrosis after

acetaminophen (paracetamol) overdose, and patients

with multiple trauma.

Gc-globulin (group-specific component globulin), also

known as vitamin D binding protein (DBP), is a

multifunctional plasma glycoprotein of molecular mass

51-58 kDa.1,2 It is structurally related to serum albumin

and acts as a carrier protein for vitamin D, but it can

also be converted by partial deglycosylation into a

macrophage activating factor known as DBP-MAF or

Gc-MAF.3 One of its most important functions,

however, is to act as an actin scavenger.4 Actin is the

most abundant protein in eukaryotic cells and is

released into the circulation by dead or dying cells.

There it can form long filaments which may trigger

intravascular coagulation if not rapidly removed. This

can lead to a condition resembling multiple organ

dysfunction syndrome (MODS).5 In the actin

scavenging system, actin is depolymerized by gelsolin

and strongly bound by Gc-globulin, allowing for the

rapid clearance of actin-Gc-globulin complexes. This

consumes Gc-globulin. Low Gc-globulin levels, both

the total level and the actin-free level, which is an

index of residual actin-scavenging capacity, can act

as prognostic markers in situations of organ damage

such as fulminant hepatic failure,6,7 acetaminophen

(paracetamol) overdose8,9 and multiple trauma.10,11

Other conditions such as septic shock may also be

associated with reduced Gc-globulin levels and

complex formation with actin,12 but this has been less

extensively studied.

Gc-globulin is an acute phase protein, whose

synthesis by the liver is increased by inflammation.

Circulating Gc-globulin may therefore show various

responses in critically ill patients, depending on the

balance between the rate and duration of Gc-globulin

depletion, due to complex formation with actin, and

the rate of new Gc-globulin synthesis.13 After

acetaminophen (paracetamol) overdose, the mean fall

in the actin-free Gc-globulin level is more marked than

the mean fall in the total Gc-globulin level.9,14

In fulminant hepatic failure, using a cutoff value of

(determined by rocket immunoelectrophoresis) gave

positive predictive values for patient non-survival of

100% for acetaminophen-related cases and 79% for

other cases, with corresponding negative predictive

values (patient survival with levels >100 µg/mL) of

53% and 60%. These predictive values are slightly

better than those obtained with the King's College

Hospital (KCH) criteria.6 In acute liver failure after

g/mL for serum total Gc-globulin on day 2 gave a

positive predictive value for the development of

hepatic encephalopathy (coma grade II) of 75%, while

the negative predictive value was 91%.9 Lee et al.14

(i.e. actin-free) Gc-globulin to predict survival in

fulminant hepatic failure, obtaining positive predictive

values of 68% for early sera and 89% for later sera.

In cases of multiple trauma, using a cutoff value

admission (determined by rocket immunoelectrophoresis)

gave a positive predictive value for patient

non-survival of 69% and a negative predictive value

(patient survival with levels >200 µg/mL) of 84%.

Sensitivity and specificity were 56% and 90%,

respectively. These values are closely comparable to

those obtained from the trauma injury and severity

score (TRISS).10

The assay is an ELISA performed in microwells coated

with a monoclonal antibody capable of binding human

Gc-globulin whether or not it is complexed with actin.

Coat-bound actin-free Gc-globulin is detected with a

horseradish peroxidase (HRP)-conjugated monoclonal

antibody whose binding to Gc-globulin is blocked by

the presence of bound actin. This is followed by color

development via incubation with a chromogenic

substrate. The assay is a rapid two-step procedure:

Step 1. Aliquots of calibrators, diluted serum

samples and any controls are incubated with HRPconjugated

detection antibody in the coated

microwells Only actin-free Gc-globulin will bind to

both coat and detection antibody, while unbound

materials are removed by washing.

Step 2. A chromogenic peroxidase substrate

containing tetramethylbenzidine (TMB) is added to

each test well. The HRP linked to the bound detection

antibody reacts with the substrate to generate a

colored product. The enzymatic reaction is stopped

chemically, and the color intensity is read at 450 nm in

an ELISA reader. The color intensity (optical density) is

a function of the concentration of actin-free Gcglobulin

originally added to each well. The results for

the calibrators are used to construct a calibration

curve from which the concentrations of actin-free Gcglobulin