Test Information

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Mannan-Binding Lectin Pathway Function Test (C4b)

Test Code: 34

Cpt Code:

86161 (x1)

Clinical Utility

Deficiency in either MBL or MASP-2 appears to predispose individuals to serious infections (e.g. pneumonitis, sepsis, osteomyelitis, gastroenteritis and meningitis) especially during childhood before the adaptive immunity has fully developed.


Enzyme Immunoassay (EIA). MBL pathway function is indirectly monitored by determining the the specific C4b-depositing capacity of patient sera with an anti-human C4 monoclonal antibody. This test has not been cleared or approved for diagnostic use by the U.S. Food and Drug Administration.

Assay Range

The assay range is approximately 135 to 3100. Results less than 200 ng/mL indicate deficiency. This range is the mean plus 3 standard deviations with sera obtained from a population of deficient individuals

Turnaround Time

Setup: Tuesday TAT: 5-7 business days from receipt of specimen

Specimen Information

serum - NY approved. 2 mL, Ambient, ship overnight at ambient temperature. For longer storage freeze and ship frozen.

1 week ambient
4 week refrigerated
> 3 mon freeze (can go through 4 freeze/thaw cycles)


Specimens are approved for testing in New York only when indicated in the Specimen Information field above.

The CPT codes provided are based on Viracor-IBT's interpretation of the American Medical Association's Current Procedural Terminology (CPT) codes and are provided for general informational purposes only. CPT coding is the sole responsibility of the billing party. Questions regarding coding should be addressed to your local Medicare carrier. Viracor-IBT assumes no responsibility for billing errors due to reliance on the CPT codes illustrated in this material.



Kilpatrick, D.C. Mannan-binding lectin and its role in innate immunity. Transfus.  Med. 2002; 12(6):335-352.

Kilpatrick, D.C. Mannan-binding lectin: clinical significance and applications.  Biochim. Biophys. Acta 2002; 1572:401-413.

Stengaard-Pederson, K. et al. Inherited deficiency of mannan-binding lectinassociated serine protease 2. N. Engl. J. Med. 2003; 349 (6):554-560.

Petersen, S. V. et al. An assay for the mannan-binding lectin pathway of complement activation. J. Immunol. Methods 2001; 257:107-116.

Moller-Kristensen, M. et al. Levels of mannan-binding lectin-associated serine protease-2 in healthy individuals. J. Immunol. Methods 2003; 282:159-167.

Kirschfink, M. and Mollnes, T.E. Modern complement analysis. Clin. Diag. Lab. Immunol. 2003; 10:982-989.

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