Table 2 Usage, turnaround time, age at test result, and yield of diagnostic genetic testing.

From: Genetic disorders and mortality in infancy and early childhood: delayed diagnoses and missed opportunities

Genetic test

Patientsa

Tests

Turnaround time,b days

Age at test result, days

Resultc N (%)

   

Median (Q1–Q3), N

 

Karyotyped

30

30

5.0

10.0

Positive: 6/30 (20)

   

(4.0–10.5), 9

(6.3–21.3), 20

Negative: 18/30 (60)

     

VUS: 2/30 (7)

     

None: 6/30 (20)

Fluorescence in situ hybridization

8

9

3.0

10.0

Positive: 2/9 (22)

   

(min–max 1.0–8.0), 3

(5.3–227.8), 4

Negative: 4/9 (44)

     

VUS: 0/9 (0)

     

None: 3/9 (33)

Chromosomal microarrayd

48

51

16.5

35.0

Positive: 8/51 (16)

   

(10.0–23.0), 40

(16.5–66.5), 41

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

82.0

Positive: 12/94 (13)

   

(13.0–34.0), 87

(41.0–182.5), 89

Negative: 79/94 (84)

     

None: 0/91 (0)

     

VUS: 7/94 (7)

Deletion/duplication analysis

22

27

21.0

73.0

Positive: 5/27 (19)

   

(14.0–41.0), 27

(40.0–139.0), 27

Negative: 21/27 (78)

     

None: 1/27 (4)

     

VUS: 0/27 (0)

Methylation analysis

5

5

8.0

69.0

Positive: 0/5 (0)

   

(6.0–24.0), 5

(11.0–179.0), 5

Negative: 4/5 (80)

     

VUS: 0/5 (0)

     

None: 1/5 (20)

Triplet repeat study

2

2

42.0

82.0

Positive: 0/2 (0)

   

(N/A), 1

(min–max 77.0–87.0), 2

Negative: 2/2 (100)

     

VUS: 0/2 (0)

     

None: 0/2 (0)

Gene paneld

20

25

48.0

106.0

Positive: 4/25 (16)

   

(32.0–56.0), 23

(54.0–231.0), 23

Negative:12/25 (48)

     

VUS: 9/25 (36)

     

None: 1/25 (4)

Mitochondrial gene testingd

5

7

81.0

147.0

Positive: 1/7 (14)e

   

(61.0–157.0), 7

(74.0–446.0), 7

Negative: 5/7 (71)

     

VUS: 3/7 (43)

     

None: 0/7 (0)

Whole-exome or whole-genome sequencingf

7

7

161.0

456.0

Positive: 3/7 (43)

   

(114.0–268.0), 7

(170.0–602.0), 7

Negative: 2/7 (29)

     

VUS: 2/7 (29)

     

None: 0/7 (0)

  1. VUS, variant of uncertain significance.
  2. aNumber of patients who had the test sent (patients may have had more than one test sent).
  3. b”Turnaround time” refers to the number of 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.
  4. c“Positive” includes pathogenic or likely pathogenic variant; “Negative” includes benign/likely benign variant; “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.
  5. dTest could have more than one category of result (e.g., one pathogenic variant and one VUS).
  6. eThis 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).
  7. fOne patient had whole-genome sequencing with a turnaround time of 294 days and a positive result.
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