haptoglobin in serum by nephlometry

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Introduction

Snomed term of haptoglobin in serum by electrophoresis is reason for this term. (also see haptoglobin in serum)

Indications

Reference interval

Principle

The Beckman Array Protein System, in conjunction with the Haptoglobin Reagent Test Kit, is intended for in vitro diagnostic quantitation of Haptoglobin of biological fluids by rate nephelometry.

Haptoglobin is a hemoglobin-binding alpha-2 glycoprotein, the levelof which is generally genetically controlled. It is produced in the liver & is rapidly degraded by the reticuloendothelial system. Free hemoglobin cannot be detected in the plasma or urine until its level exceeds the binding capacity of haptoglobin. During an episode of hemolysis the plasma haptoglobin level falls to zero, as it is constantly being combined with hemoglobin & rapidly removed by the reticuloendothelial cells. Its low level is therefore a good indicator of hemolysis. It may remain depleted for 5-7 days after a hemolytic episode, since its synthesis in the liver may require up to 2 weeks.

Clinical significance

Increases

Decreases

Specimen

No special patient preparation is required. 200 uL of serum. Store sample in freezer until ready for assay. Highly lipemic samples may result in inaccurate determination & should be redrawn on a fasting patient.

Antigen Excess

When running IgG, IgA, IgM, Kappa, Lambda, Haptoglobin or CSF Albumin it is sometimes possible to encounter specimens (for example, monoclonal proteins) which contain protein concentrations high enough to be in excess of the antibody in the reaction cell. In these cases, an antigen excess situation would lead to falsely low results if not detected. For this reason the Array antigen excess check monitors the kinetic reactions of these samples to ascertain if the potential for this condition of antigen excess exists. If the monitoring detects this potential situation, the system will make a 3rd injection of antigen excess solution to verify whether free antibody remains in the reaction cell or not. If this 3rd injection causes further reaction, free antibody is available & the result is reported. However, if the 3rd injection does not trigger further reaction, the sample will be reassayed at a higher dilution.

More general terms

Additional terms

References

  1. Beckman Array Protein System Operating Manual.
  2. Teitz, Norbert W.: Textbook of Clinical Chemistry, W. B. Saunders, Co, Philadelphia, PA, pp. 592-594, 1986.
  3. Bauer, John D., Ackerman, Phillip G., Toro, Gelson: Clinical Laboratory Methods, The C.V. Mosby Co., St. Louis, MO, 8th Edition; pp. 140-141.
  4. MedlinePlus: Haptoglobin http://www.nlm.nih.gov/medlineplus/ency/article/003634.htm
  5. Haptoglobin Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0050280.jsp