Diagnostic Yield of Oral Swab Testing by TB-LAMP for Diagnosis of Pulmonary Tuberculosis

Figures & data

Table 1 Demographic and Clinical Characteristics of Individuals with Symptoms Suggestive of Pulmonary Tuberculosis

Characteristics	All Patients (n=101)
Median age (range), years	43.5 (17.0–88.0)
Male sex, n (%)	69 (74.6)
Residence
Resident	61 (60.4)
Float	40 (39.6)
Comorbidity/ies
Diabetes	16 (15.8)
Hypertension	10 (9.9)
Cardiac disease	8 (7.9)
Immunologic dysfunction	4 (4.0)
Kidney dysfunction	4 (4.0)
Hepatitis	3 (3.0)
Others	2 (2.0)

Figure 1 Participant enrollment.

Abbreviation: OS, oral swab.

Figure 2 Venn diagram showing the distribution of 101 patients for detection of MTB by using smear microscopy, MGIT, Xpert, and oral swab testing. Among 101 patients included, 41 were positive for MTB by oral swab testing, whereas, 45, 38, and 21 samples were positive by Xpert, MGIT and smear microscopy, respectively.

Table 2 Detection of MTB with TB-LAMP from Various Oral Swab Samples

Specimen	n	TP	FP^a	FN	TN	Sensitivity (95%CI)	Specificity (95%CI)	PPV (95%CI)	NPV (95%CI)
Morning	101	23	2	23	53	50.0 (35.6–64.4)	96.4 (91.4–100.0)	92.0 (81.4–100.0)	69.7 (59.4–80.1)
Night	101	15	1	31	54	32.6 (19.1–46.2)	98.2 (94.7–100.0)	93.8 (81.9–100.0)	63.5 (53.3–73.8)
Spot	101	17	1	29	54	37.0 (23.0–50.9)	98.2 (94.7–100.0)	94.4 (83.9–100.0)	65.1 (54.8–75.3)
Morning + Spot	101	31	3	15	52	67.4 (53.8–80.9)	94.5 (88.5–100.0)	91.2 (81.6–100.0)	77.6 (67.6–87.6)
Night + Spot	101	28	2	15	52	60.9 (46.8–75.0)	96.4 (91.4–100.0)	93.3 (84.4–100.0)	74.6 (64.5–84.8)
Morning + Night	101	32	2	14	53	69.6 (56.3–82.9)	96.4 (91.4–100.0)	94.1 (86.2–100.0)	79.1 (69.4–88.8)
All	101	38	3	8	52	82.6 (71.7–93.6)	94.5 (88.5–100.0)	92.7 (84.7–100.0)	86.7 (78.1–95.3)

Note: ^aFP is determined when Xpert and MGIT on sputum specimens are used as gold standard.

Abbreviations: TP, true positive; FP, false positive; FN, false negative; TN, true negative; PPV, positive predictive value; NPV, negative predictive value.

Figure 3 Relationship of OS-LAMP results with bacterial load (A). Relationship of OS-LAMP results with bacterial load by Xpert; The Xpert-generated cycle threshold (Ct) value of Probe A was used as an indicator for bacterial load. (B) Relationship of OS-LAMP results with bacterial load by MGIT.