Key Features |
Navigene GC-MS ( Next GenerationTech) |
MS-MS ( Standard tech) |
Sample required of Analysis |
- Non invasive, Urine sample, easy to collect
- Parent can do collection at home
- Urine contains more than 3000 detectable metabolites7 many exist in higher concentration than blood and hence detectable easily
|
- Invasive, Heal prick blood spot samples
- Technical expertise required chances of sepsis; severe pain impulse possible
- Blood contains similar number of detectable metabolites, but many may not be in high concentration as urine7 and hence not detectable.
- Certain IEMs do not alter blood amino acid and acylcarnitine profile and hence can’t be detected in blood samples.
|
Disorders Covered |
Comprehensive , Covers 110 disorders |
Covers upto 45 disorders |
Time to Diagnosis |
Faster : Screening and confirmation in ONE STEP
A GOLD STANDARD for Diagnosis of Organic academia since 196011,12,13 |
Slower : Two Step Process Screen Positive Follow up repeat test Still positive Confirmatory test Diagnosis |
Accuracy of results |
Consistent & Reliable: A very high positive predictive value,
Highly sensitive & specific and hence recommended by ACMG for DIAGNOSIS of screen positive cases by MS-MS |
High false positives is a major issue that plagues MS-MS for years8 |
Methodology used for Analysis |
Planar Method used , Multiple markers per disorders
PKU : Phe , PA , 2HPA, PL, PPA
MSUD : Leu , Isoleu, Val, 2 HIV, 3HIV, 2HIC Unique picture leads to immediate and exact diagnosis |
Usually single marker analyzed per disorder , Non Specific
PKU : Phe
MSUD : Leu & Val disorders , and hence a more detailed analysis is required to pin point and confirm
|
Additional benefits |
Differential Diagnosis of the disorders possible
GC-MS can differentiate6between MMA & PA as it looks at multiple marker compounds and the markers for both differ in this analysis. |
Differential diagnosis not possible
E.g Carnitine compound-C3 Acylcarnitine6 is elevated in both MMA and PA, hence differential diagnosis not possible and doing a GC-MS analysis is a must to differentiate |
Interference |
Chromatography separates potential interfering compounds, such as drugs and exogenous chemicals and hence no interference observed in GC-MS analysis with such compounds |
Certain drugs and exogenous Chemicals can interfere with , detection of some acylcarnitines12 e.g. Valproic acid, cefotaxime, dectrose etc and hence the sensitivity/specificity goes down |
Turn Around time |
CMedium through put :
Take 15-18 min per sample |
High through put :
Takes a few min ~ 2 min per sample and hence feasible for mass screening |
Non-invasive