Overview


This test assists in the diagnosis of autoimmune myasthenia gravis (MG)

Test code:

LRP4 CBA

Abbreviations:

LRP4 Ab, LRP4 CBA

Methodology:

In-house fixed cell-based assay (CBA)

Validation:

Laboratory Developed Test (LDT)

Requirements


Specimen type:

Serum

Minimum volume:

0.5 mL

Preferred volume:

5 mL

Rejection criteria:

Grossly hemolytic, lipemic, or icteric. If the sample arrives at room temperature.

Our offices are only able to receive samples Mon-Fri, so samples must be shipped Mon-Thur. Samples arriving over the weekend may need to be re-drawn.

Specimen


Specimen collection:

No patient preparation is required for sample collection.
Draw blood in tube(s) with SST activator (5mL gold top or 8.5mL tiger top).
Invert tubes 8 times to ensure complete mixing.

Specimen handling:

Centrifuge SST tubes at 1800 - 2200 x g for 10-15 minutes
Draw off serum (top layer) into Aliquot tubes with pipette, ensuring not to take gel or RBC (middle/bottom layers)
Store Aliquot tubes in refrigerator (2°C - 8°C) until shipping.

Specimen stability:

Serum samples may be stored:
Up to 1 month refrigerated (2 - 8⁰C)
Up to 2 weeks frozen (-20⁰C)
Up to 3 months at ultra-low (-80⁰C – -70⁰C)
Up to 4 freeze / thaws

Performance


Testing frequency:

Once a week (3-day testing procedure)

Turnaround time:

1-3 weeks

Reference range:

N/A

Additional Information


  • This test was developed and its performance determined by Neurocode USA Inc. It has not been cleared or approved by the Food and Drug Administration.
  • Please indicate if patients are on immunomodulating treatments as these may interfere with testing.
  • Causal antibodies cannot be identified in about 10% of MG cases. Therefore, a positive result is specific for the diagnosis of AChR ab myasthenia gravis (MG), but a negative result does not rule out an MG diagnosis.