Table 2.
Usage, turnaround time, age at test result, and yield of diagnostic genetic testing.
| Genetic Test | Patientsa | Tests | Turnaround Timeb, days |
Age at Test Result, days |
Resultc N (%) |
|---|---|---|---|---|---|
| Median (Q1–Q3), N |
|||||
| Karyotyped | 30 | 30 | 5.0 (4.0–10.5), 9 | 10.0 (6.3–21.3), 20 | Positive: 6/30 (20) |
| Negative:18/30 (60) | |||||
| VUS: 2/30 (7) | |||||
| None: 6/30 (20) | |||||
| Fluorescence in situ hybridization | 8 | 9 | 3.0 (min-max 1.0–8.0), 3 | 10.0 (5.3–227.8), 4 | Positive: 2/9 (22) |
| Negative: 4/9 (44) | |||||
| VUS: 0/9 (0) | |||||
| None: 3/9 (33) | |||||
| Chromosomal microarrayd | 48 | 51 | 16.5 (10.0–23.0), 40 | 35.0 (16.5–66.5), 41 | Positive: 8/51 (16) |
| Negative: 30/51 (59) | |||||
| VUS: 11/51 (22) | |||||
| None: 3/51 (6) | |||||
| Single gene testing (sequencing or targeted mutation analysis)d | 47 | 94 | 22.0 (13.0–34.0), 87 | 82.0 (41.0–182.5), 89 | Positive: 12/94 (13) |
| Negative: 79/94 (84) | |||||
| VUS: 7/94 (7) | |||||
| None: 0/91 (0) | |||||
| Deletion/duplication analysis | 22 | 27 | 21.0 (14.0–41.0), 27 | 73.0 (40.0–139.0), 27 | Positive: 5/27 (19) |
| Negative: 21/27 (78) | |||||
| VUS: 0/27 (0) | |||||
| None: 1/27 (4) | |||||
| Methylation analysis | 5 | 5 | 8.0 (6.0–24.0), 5 | 69.0 (11.0–179.0), 5 | Positive: 0/5 (0) |
| Negative: 4/5 (80) | |||||
| VUS: 0/5 (0) | |||||
| None: 1/5 (20) | |||||
| Triplet repeat study | 2 | 2 | 42.0 (N/A), 1 | 82.0 (min-max 77.0–87.0), 2 | Positive: 0/2 (0) |
| Negative: 2/2 (100) | |||||
| VUS: 0/2 (0) | |||||
| None: 0/2 (0) | |||||
| Gene paneld | 20 | 25 | 48.0 (32.0–56.0), 23 | 106.0 (54.0–231.0), 23 | Positive: 4/25 (16) |
| Negative:12/25 (48) | |||||
| VUS: 9/25 (36) | |||||
| None: 1/25 (4) | |||||
| Mitochondrial gene testingd | 5 | 7 | 81.0 (61.0–157.0), 7 | 147.0 (74.0–446.0), 7 | Positive: 1/7 (14)e |
| Negative: 5/7 (71) | |||||
| VUS: 3/7 (43) | |||||
| None: 0/7 (0) | |||||
| Whole exome or whole genome sequencingf | 7 | 7 | 161.0 (114.0–268.0), 7 | 456.0 (170.0–602.0), 7 | Positive: 3/7 (43) |
| Negative: 2/7 (29) | |||||
| VUS: 2/7 (29) | |||||
| None: 0/7 (0) | |||||
Number of patients who had the test sent (patients may have had more than one test sent).
Turnaround time refers to the difference in days between the date the specimen was received by the lab and the date of the result report. This information was not available for all tests reviewed.
VUS, variant of unknown significance; “Positive” includes pathogenic or likely pathogenic variants; “Negative” includes benign/likely benign variants; “None” indicates that there was no result from the test or the test result was unknown. A single pathogenic variant in a gene associated with an autosomal recessive condition (i.e. CFTR) was not considered a positive result.
Test could have more than one category of result (e.g. one pathogenic variant and one variant of unknown significance).
This patient had a “positive” result on genetic testing but was not determined to have a molecular genetic diagnosis made (it was unclear whether the variant identified was responsible for the patient’s presentation).
One patient had whole genome sequencing with a turnaround time of 294 days and a positive result.