Table 1.
Concentration of acylcarnitines and ratios relevant for profiling beta-ketothiolase in the newborn screening specimens from patient 1
| Relevant acylcarnitines/ratios | Specimen 1–DOL 3 | Specimen 2–DOL 13 | MA | CLR tools | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Original | Retest | Original | Retest | cut-off | 99th%ile of normal | 1st%ile of BKT | 5th%ile of BKT | Target cut-offs | |||||
| Value | Z-score | Value | Z-score | Value | Z-score | Value | Z-score | ||||||
| C5:1 | 0.04 | 3.34 | 0.05 | 3.98 | 0.05 | 3.98 | 0.04 | 3.34 | 0.08 | 0.06 | 0.07 | 0.15 | 0.06–0.15 |
| C5OH | 0.18 | 1.44 | 0.16 | 1.09 | 0.14 | 0.7 | 0.18 | 1.44 | 0.8 | 0.36 | 0.49 | 0.65 | 0.36–0.82 |
| C4OH | – | – | 0.1 | −0.48 | – | – | 0.1 | −0.48 | 0.75 | 0.47 | 0.58 | 0.6 | 0.47–0.81 |
| C0 | 29.41 | 0.74 | 55.52 | 2.59 | 26.01 | 0.38 | 28.27 | 0.63 | – | 50.55 | 9.3 | 11.19 | – |
| C5 | 0.37 | 2.5 | 0.27 | 1.52 | 0.33 | 2.14 | 0.38 | 2.58 | – | 0.38 | 0.1 | 0.13 | – |
| C8 | 0.06 | −1.21 | 0.05 | −1.86 | 0.1 | 0.61 | 0.09 | 0.24 | – | 0.17 | 0.03 | 0.04 | – |
| C16 | 1.88 | −1.44 | 1.72 | −1.7 | 0.74 | −4.18 | 0.63 | −4.65 | – | 5.73 | 1.13 | 1.32 | – |
| C5OH × C5:1 | 0.007 | 3.08 | 0.008 | 3.28 | 0.007 | 3.08 | 0.007 | 3.08 | 0.02 | – | – | – | – |
| C5 × C5:1/C5OH | 0.082 | 2.83 | 0.084 | 2.88 | 0.118 | 3.52 | 0.084 | 2.88 | 0.05 | – | – | – | – |
| C5OH/C8 | 2.74 | 1.77 | 3.16 | 2.12 | 1.40 | 0.22 | 2.00 | 1.01 | 10 | 7.81 | 3.68 | 4.95 | 7.81–10 |
| C5OH/C0 | 0.006 | – | 0.002 | – | 0.005 | – | 0.006 | – | – | 0.02 | 0.02 | 0.02 | 0.018–0.026 |
| C4OH/C16 | – | – | 0.06 | – | – | – | 0.16 | – | – | 0.13 | 0.27 | 0.28 | 0.13–0.28 |
BKT beta-ketothiolase deficiency. Concentrations and values shown are those reported originally and after retesting after diagnosis (at time of retest additional markers including C4OH were also being analyzed for routine screening). Values for the 99th percentile of the normal population, and the 1st & 5th percentiles in confirmed BKT cases, and recommended cut-offs for the relevant markers and ratios in the CLIR-R4S database are shown [http://www.clir-r4s.org/; accessed 05/22/2017]. C5:1, C5OH and C4OH are expected to be high in BKT. C0, C5, C8, and C16 are utilized for calculating ratios and scores to risks of BKT by the NBS Analytical Tools in the CLIR-R4S databases and by the New England Newborn Screening Program (NENSP). C5OH × C5:1, [C5 × C5:1/C5OH] and C5OH/C8 are utilized by NENSP for evaluating BKT profiles/risk of disorder. C5OH/C8, C5OH/C0 and C4OH/C16 are required by calculating a score/risk of disorder by the CLIR-R4S in the current BKT Post-Analytic Tool [BKT 009 2012-01-08 Single-D]. The score for patient 1 calculated using the BKT Post-Analytic Tool was “0” in both specimens with the interpretation “Score Profile is not informative for BKT”