Table 1 Summary of performance characteristics of PCR assay tested in this study and reported literature

ETEC

LT (labile toxin)

ST (stable toxin)

No of samples: 59

11.5 (7.2-12.0) years

≤ 3 years: 13 samples

5–13 years: 46 samples

PPA:62.7 (49.2-75.0)

NPA:70.0 (55.4-82.1)

Stratified by duration:

≤ 3 years: PPA: 69.2 (38.6–90.9)

NPA: 66.7 (47.2–82.7)

5–13 years: PPA: 60.8 (45.4–74.9)

NPA: 75.0 (50.9–91.3)

Sample size: 109 (10 ETEC positive)

Comparator: Culture + PCR of 5 colonies

PCR platform: TAC

Storage duration: 2–4 years (10)

PPA:100.0 (69.2–100.0)

NPA (ETEC LT): 55.0 (41.6–67.9)

NPA (ETEC ST): 69.7 (57.1–80.4)

Campylobacter

No of samples:21

2.6 (2.6-11.4) years

≤ 3 years: 11

5-13 years: 10

PPA:66.6 (43.0–85.4)

NPA:69.3 (58.6–78.7)

Stratified by duration:

≤ 3 years: PPA: 63.6 (30.8–89.0)

NPA: 68.8 (50.0–83.8)

5–13 years: PPA: 70.0 (34.8–93.3)

NPA: 69.6 (56.0–81.2)

Sample size: 1557 (35 Campylobacter positive)

Comparator: Culture

PCR platform: BioFire FilmArray GI panel

Storage duration: days-weeks (4)

PPA:97.1 (85.1–99.9)

NPA:98.4 (97.7–99.0)

Shigella/EIEC

No of samples:10

7.6 (6.7–10) years

5–13 years: 10

PPA:100.0 (69.2-100.0)

NPA:82.8 (74.0–89.6)

Sample size: 1557 (49 Shigella/EIEC positive)

Comparator: Culture (PCR for EIEC)

PCR platform: BioFire FilmArray GI panel

Storage duration: days-weeks (4)

PPA:95.9 (86.0–99.5)

NPA:98.5 (99.5–130.0)

Norovirus

No of samples:19

2.6 (2.6–2.6) years

≤ 3 years: 19

PPA:36.8 (16.2–61.6)

NPA:80.0 (70.2–87.6)

Sample size: 1557 (55 Norovirus positive)

Comparator: RT-PCR

PCR platform: BioFire FilmArray GI panel

Storage duration: days-weeks (4)

PPA:94.5 (84.9–98.9)

NPA:98.8 (98.1–99.3)

ETEC

No of samples:70; 10.5 (6.9–12.0) years

≤ 3 years: 14

5–13 years: 56

PPA:55.7 (43.3–67.6)

NPA:85.3 (80.0–90.0)

≤ 3 years: PPA: 57.1 (28.8–82.3)

NPA: 86.0 (75.0–93.3)

5–13 years: PPA: 55.4 (41.4–68.6)

NPA: 85.0 (77.6–90.8)

Campylobacter

No of samples: 59; 10.4 (2.6–11.8) years

≤ 3 years: 28

5–13 years: 31

PPA:62.7 (49.2–75.0)

NPA:82.2 (76.2–87.2)

≤ 3 years: PPA:71.4 (51.3–86.8)

NPA: 84.0 (70.8–92.8)

5–13 years: PPA: 54.8 (36.0–72.6)

NPA: 81.6 (74.4–87.4)

Shigella

No of samples: 62; 6.0 (2.5–7.6) years

≤ 3 years: 6

5–13 years: 56

PPA:88.7 (78.1–95.3)

NPA:86.4 (81.0–91.0)

≤ 3 years: PPA: 16.6 (1.0–64.1)

NPA: 94.4 (86.4–98.4)

5–13 years: PPA: 96.4 (87.6–99.6)

NPA: 81.8 (74.0–88.2)

Norovirus

No. of samples: 27; 2.6 (2.6–2.6) years

PPA:51.8 (32.0–71.3)

NPA:97.8 (95.0–99.3)

N/A (all samples stored ≤ 3 years)

ETEC

No. of paired samples: 52;

median duration of FTA card storage: 8.8 (2.6–11.8) years

≤ 3 years: 19

5–13 years: 33

PPA: 75.0 (63.2–86.8)

NPA: 91.2 (83.8–98.6)

Stratified by duration:

≤ 3 years: PPA: 73.6 (48.8–90.8)

NPA: 91.6 (73.0–98.9)

5–10 years: PPA: 75.8 (57.7–88.9)

NPA: 90.9 (75.6–98.0)

Total sample size: 187

ETEC positive TAC on stool: 85

Storage duration: 2 years (9)

PPA:90.6 (82.2–96.0)

NPA:97.6 (93.3–99.5)(3)

Campylobacter

No. of paired samples: 41; median storage duration: 7.0 (2.6–11.8) years

≤ 3 years: 17

5–10 years: 24

PPA:58.5 (42.1–73.6)

NPA:88.2 (78.1–94.8)

Stratified by duration:

≤ 3 years: PPA: 47.0 (22.9–72.2)

NPA: 92.3 (74.8–99.0)

5-13 years: PPA: 66.6 (44.6–84.4)

NPA: 85.7 (71.4–94.6)

Total sample size: 187

Campylobacter positive TAC on stool: 11

Storage duration: 2 years (9)

PPA:90.9 (58.7–99.8)

NPA:100.0 (98.0–100.0)(3)

Shigella

Shigella positive TAC on stool: 27; median storage duration: 7.7 (6.0–11.3) years

≤ 3 years: 5

5–10 years: 22

PPA: 66.6 (46.0-83.4)

NPA: 92.6 (84.8–97.2)

Stratified by duration:

≤ 3 years: PPA: 40.0 (5.2–85.3)

NPA: 94.7 (82.2–99.4)

5–13 years: PPA: 72.7 (49.8–89.2)

NPA: 90.9 (78.3–97.4)

Total sample size: 187

Shigella positive TAC on stool: 18

Storage duration: 2 years (9)

PPA:88.9 (65.2-98.6)

NPA:99.4 (96.8-99.9)(3)

Norovirus

No of samples:19; median duration of FTA card storage: 2.6 (2.6–2.6) years

PPA:28.0 (12.0–49.4)

NPA:92.8 (85.1–97.3)

Stratified by duration:

≤ 3 years: PPA: 36.4 (10.9–69.2)

NPA: 81.2 (636–92.8)

5–13 years: PPA: 21.4 (4.6–50.8)

NPA: 100.0 (93.2–100.0)

Total sample size: 187

Norovirus positive TAC on stool: 24

Storage duration: 2 years (9)

PPA:38.0 (18.8–60.0)

NPA:100.0 (98.9–100.0)(3)