Intermediate
Technical
IVT
second-tier testing
Additional laboratory analysis performed on the original blood spot to reduce false positives before clinical follow-up.
Full Definition
Second-tier testing involves performing supplementary assays on dried blood spots that initially screened positive, using the same specimen to provide more specific information before referring families for clinical evaluation. This approach may include DNA analysis, enzyme activity measurement, or additional biomarker testing. Second-tier strategies significantly reduce false positive rates, decreasing family anxiety and healthcare system burden while maintaining sensitivity for true cases.
Usage
Usage note: Distinguish from diagnostic confirmation testing performed at specialty centers.
In Context
- "Second-tier testing for galactosemia reduced false positives from blood transfusions by 85%." — Program evaluation
- "The laboratory implemented second-tier molecular testing for SCID screening." — Method validation
Also known as
reflex testing
supplemental screening
Don't confuse with
repeat testing
confirmatory testing