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Chapter 38

The Binding Site Optilite is an automated, bench-top, random-access turbidimeter (Figure 38.2). IgAκ, IgAλ, IgMκ and IgMλ Hevylite assays are currently available for use on the instrument, and IgGκ and IgGλ assays are in development.

The Hevylite assay times are 11 minutes for IgMκ and IgMλ assays and 18 minutes for IgAκ and IgAλ. Calibration curves are generated using a single calibrator fluid which is diluted by the instrument, and curves are validated using the two control fluids supplied with the kits.

If a Hevylite result is outside the initial measuring range at the standard (1+9) dilution, the sample is automatically re-diluted by the instrument. Assay parameters define two higher and one lower automatic re-dilution; very high level samples may require further offline dilution.

Hevylite assays have good within-run and between-run precision [891][892][893][894]. Performance characteristics are summarised in Table 38.2. Antigen excess (prozone) parameters exist for IgM Hevylite assays. Samples detected as being in antigen excess are automatically flagged by the instrument with a “prozone detected” flag and the sample is automatically re-assayed at the higher dilution.

IgAκ IgAλ IgMκ IgMλ
Range

(at standard dilution)

0.18 - 11.20 g/L

(1+9)

0.16 - 10.40 g/L

(1+9)

0.2 - 5.0 g/L

(1+9)

0.18 - 4.50 g/L

(1+9)

Sensitivity

(neat assay dilution)

0.018 g/L

(1+0)

0.016 g/L

(1+0)

0.02 g/L

(1+0)

0.018 g/L

(1+0)

Assay time 18 min 18 min 11 min 11 min
Precision: within run 2.1% at 0.30 g/L 1.3% at 0.30 g/L 1.1% at 0.10 g.L * 1.5% at 0.06 g/L *
1.7% at 0.85 g/L 1.7% at 0.94 g/L 1.2% at 0.15 g/L * 1.2% at 0.09 g/L *
2.8% at 1.65 g/L 2.0% at 1.56 g/L 1.2% at 0.22 g/L * 0.9% at 0.13 g/L *
1.9% at 2.45 g/L 2.3% at 1.63 g/L 1.0% at 0.33 g/L 1.1% at 0.36 g/L *
3.1% at 3.38 g/L 1.9% at 2.32 g/L 1.1% at 1.19 g/L 1.5% at 0.76 g/L
1.4% at 9.12 g/L 1.3% at 8.58 g/L 1.2% at 2.05 g/L 1.1% at 1.22 g/L
1.7% at 2.60 g/L 0.8% at 1.46 g/L
1.5% at 3.94 g/L 1.4% at 3.90 g/L
Precision: between run 3.1% at 0.3 g/L 1.8% at 0.30 g/L 2.1% at 0.10 g/L * 0.9% at 0.06 g/L
2.2% at 0.85 g/L 1.1% at 0.94 g/L 2.7% at 0.15 g/L * 1.4% at 0.09 g/L
2.2% at 1.65 g/L 4.3% at 1.56 g/L 3.2% at 0.22 g/L * 1.4% at 0.13 g/L
2.9% at 2.45 g/L 1.8% at 1.63 g/L 4.5% at 0.33 g/L 1.6% at 0.36 g/L
3.4% at 3.38 g/L 2.5% at 2.32 g/L 3.8% at 1.19 g/L 1.7% at 0.76 g/L
1.7% at 9.12 g/L 1.6% at 8.58 g/L 4.5% at 2.05 g/L 1.5% at 1.22 g/L
5.0% at 2.60 g/L 1.4% at 1.46 g/L
4.5% at 3.94 g/L 1.1% at 3.90 g/L

Table 38.2. HLC assay performance on the Binding Site Optilite analyser. (1+9): 1/10 sample dilution; (1+0): Neat sample dilution; * precision assessed at 1+0 sample dilution.

Questions

  1. Which Hevylite assays have antigen excess (prozone) parameters?

Answers

  1. The IgM Hevylite assays have prozone parameters on the Binding Site SPAPLUS and Optilite analysers and the Siemens BNII.
VIEW ANSWERS

Figures

References

    • 1. Kerr J, Ahaliwal S, Kausar S, Murphy F, Harding S. Evaluation of serum IgM Hevylite assays; IgM kappa and IgM lambda for use on the Binding Site Optilite analyser. Clinical Chemistry 2015;61:A201a
    • 2. Kerr J, Dhaliwal S, Kausar S, Murphy F, McEntee D, Harding S. Performance of serum IgM Hevylite assays; IgM kappa and IgM lambda for use on the binding site Optilite analyser. Clinical Chemistry and Laboratory Medicine 2015;53:T280a
    • 3. Southan L, Brown A, Coley M, Kaur A, McEntee D, Harding S, Showell P. Performance of Hevylite IgA kappa and IgA lambda assays for use on the Binding Site Optilite protein analyser. Clinical Chemistry and Laboratory Medicine 2015;53:T279a
    • 4. Southan L, Brown A, Coley M, Kaur A, Showell P. Performance of serum IgA kappa and IgA lambda assays for use on the Binding Site Optilite protein analyser. Clinical Chemistry 2015;61:A187a