| Test: | Measles Virus Antibody, IgG |
| Synonym: | Measles Virus Titer, Rubeola IgG Antibody (Measles) |
| Method: | Enzyme-Linked Immunosorbent Assay |
| Availability: | Test performed weekly on Mondays for specimens received by 0800; results on same day. |
| Specimen: | Blood |
| Collection Device: | One 6.0 mL SST (Gold) tube or one 6.0 mL Clot (Red) tube |
| Volume: | 0.5 - 2.0 mL serum |
| Storage/Transport: | Separate serum ASAP and transfer to clean tube. Refrigerate at 2-8°C. Sender should contact the NPHL by email or phone before shipping. Ship specimen Monday -Thursday overnight to avoid weekend deliveries. Refrigerated specimen should be shipped on cold packs. Package and ship as Category B, Biological Substance, UN3373. See instructions and shipping address at http://nphl.org/ |
| Unacceptable: | Severely lipemic, icteric or hemolyzed samples; heat-activated serum; multiple freeze thaw cycles, specimens stored at ≤ 40°C |
| Specimen Stability: | After separation from cells: ambient, < 8 hours; refrigerated (2-8°C), 72 hours; frozen (≥ -40°C), 1 year |
| Reference Interval: | NEGATIVE: No detectable measles IgG antibody. EQUIVOCAL: Borderline levels of IgG antibody to measles virus. (Repeat testing in 10-14 days is recommended). POSITIVE: Measles virus IgG antibody detected. |
| Reportable Disease: | A four-fold rise in titer between the acute and convalescent sera is reportable (see comment). |
| Comments: | Confirmation of Measles by detection of IgG antibody levels requires testing of paired sera. Acute and convalescent sera with index values of < 0.75 and > 0.99, respectively, have been shown to represent a ≥ 4-fold increase in titer. In cases where an acute serum index value is > 0.75, a 3.2 fold increase in index ratio (convalescent serum IV / acute serum IV) is indicative of a significant antibody increase. Index ratios between 1.5 and 2.1 are considered equivocal and submission of a new convalescent serum after two weeks is recommended. For additional interpretive information, contact the laboratory. When paired testing is considered, convalescent specimens must be received within 30 days from receipt of acute specimens. A positive result is indicative of current or past infection and in the absences of current clinical symptoms, may also indicate immunity. Testing performed at CDC. Pre-Approval needed from state or local health department. Send approval to NPHL@unmc.edu or call (402) 559-9444. |
| Revised: | 2/24/2015 |