TRU Block is a range of powerful immunoassay blockers capable of blocking interference created by various heterophilic antibodies (HA) and rheumatoid factor (RF).
TRU Block ™ A POWERFUL WAY TO BLOCK HAMA, HA & RF INTERFERENCE
TRU Block™ is a range of powerful immunoassay blockers capable of blocking interference created by various heterophilic antibodies (HA) and rheumatoid factor (RF).
What causes Interference? Immunoassay interference is a general term for substances that can change the outcome of an assay by causing a false positive or false negative test result. Examples of potentially interfering particles include endogenous antibodies such as heterophilic antibodies (HA) (e.g. HAMA) and rheumatoid factor (RF). Double mouse monoclonal assays and competitive assays are specifically prone to HA and RF interference and require a specialized blocker to ensure the assay’s accuracy. A blocker such as TRU Block ™ , contains specific binders directed against all types of heterophilic interference. Once bound to the interfering antibodies, the blocker prevents further binding of HA and RF to other assay components through steric hindrance.
Interfering HA (e.g. HAMA) TRU Block ™
TRU Block ™
IgM RF
Detection Antibody (mouse origin) Capture Antibody (mouse origin) Antigen
Blocking Buffer
TRU Block ™ Range
Product
Cat. Number
Protein Concentration
Application
Single-step dilution with recommended dilution of 1:1000 to 1:10
TRU Block ™ Ready
8001
ELISA & LF
TRU Block ™ ULTRA
8000
Range: 24 - 26 mg/mL Range: 24 - 26 mg/mL Range: 24 - 26 mg/mL
ELISA, CLIA & LF
TRU Block ™
A66800H A66802H A66803H
ELISA & CLIA
TRU Block ™ 2 TRU Block ™ 3
CLIA & LF
24.3 mg/mL
ELISA
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TRU Block ™ Performance TRU Block ™ is a powerful HAMA and RF blocking agent that can be used in double mouse monoclonal sandwich assays to reduce assay interference. Its advanced blocking performance has been proven by customers who use this blocker in commercial immunoassays. In-house studies (shown below) have also demonstrated TRU Block ™ to be an effective blocker compared to mouse IgG and supplier S active HAMA blocker.
CA19-9 Assay & BRH56382 HAMA Sera
CA19-9 Assay & SD386-1 HAMA Sera
2.5
3
Unblocked HAMA Signal
Unblocked HAMA Signal
2.5
2
2
1.5
1.5
1
1
0.5
0.5
No Blocker
TRU BLOCK ™
Supplier S Mouse IgG 5 μg/mL 1.25 μg/mL 2.5 μg/mL 0.625 μg/mL
No Blocker
TRU BLOCK ™
Supplier S Mouse IgG 5 μg/mL 1.25 μg/mL 2.5 μg/mL 0.625 μg/mL
No Blocker
No Blocker
FSH Assay & BRH56382 HAMA Sera
FSH Assay & Roche (Type 1) HAMA Sera
0.5 1 1.5 2 2.5 3
0.2 0.4 0.8 0.6 1.0 1.4 1.2 1.6
Unblocked HAMA Signal
Unblocked HAMA Signal
No Blocker
TRU BLOCK ™
Supplier S Mouse IgG 5 μg/mL 1.25 μg/mL 2.5 μg/mL 0.625 μg/mL
No Blocker
TRU BLOCK ™
Supplier S Mouse IgG 5 μg/mL 1.25 μg/mL 2.5 μg/mL 0.625 μg/mL
No Blocker
No Blocker
CA19-9 Assay & A12916H RF Sera (Diluted 1:4)
In-house RF Assay & A01270H RF Sera (Diluted 1:5) Unblocked RF Signal
1.2
0.2 0.4 0.8 0.6 1.0 1.4 1.2 1.6
1
Unblocked RF Signal
0.8
0.6
0.4
0.2
No Blocker
TRU BLOCK ™
Supplier S Mouse IgG
No Blocker
TRU BLOCK ™ Supplier S Mouse IgG Rabbit IgG 5 μg/mL 2.5 μg/mL 1.25 μg/mL
5 μg/mL
2.5 μg/mL
No Blocker
1.25 μg/mL
No Blocker
ASSAY METHOD: Three different double mouse monoclonal sandwich assays (a commercial CA19-9, a commercial FSH and an in-house RF assay) were used to compare the performance of TRU Block ™ against mouse IgG and supplier S active HAMA blocker. To quantify the relative amount HAMA or RF activity in each human sera sample within an assay, the assay was performed as per the manufacturer’s instructions using a sample diluent buffer containing no mouse IgG or other blocker. Blocking solutions containing either TRU Block ™ , mouse IgG or supplier S blocker were prepared using the same sample diluent buffer at four different concentrations (5 μg/mL, 2.5 μg/mL, 1.25 μg/mL and 0.625 μg/mL). The effectiveness of each blocker was determined by the relative suppression of HAMA or RF signal (i.e. comparing the absorbance of samples with no blocker to those with various blockers) . Native HAMA positive sera samples were obtained from Scantibodies, Inc. (SD386-1) and BioReclamation (BRH56382). Another sample was obtained from Roche (Roche Type 1) which contains pooled normal human serum spiked with Roche proprietary HAMA. RF sera samples (MLS Cat No. A12916H and A01270H) were obtained internally and are available for purchase from Meridian’s product catalog (www.meridianbioscience.com/lifescience). The study results demonstrate that TRU Block ™ is equivalent to or better than a supplier S active blocker on all HAMA and RF sera samples tested.
Life Science Division 5171 Wilfong Road, Memphis, TN 38134 901-382-8716 • 800-327-6299 • info@meridianlifescience.com
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05/19
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