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Table 2 Contingency tables detailing comparison of surrogate markers to the ‘gold-standard’ for UTI diagnosis (bacterial culture), in a cohort of renal transplant recipients

From: Urinary ATP and visualization of intracellular bacteria: a superior diagnostic marker for recurrent UTI in renal transplant recipients?

(1) Leukocyte esterase*

(2) Nitrite

(3) Combined dipsticks

 

Culture positive

Culture negative

 

Culture positive

Culture negative

 

Culture positive

Culture negative

Leukocyte positive

6 (11%)

40 (76%)

Nitrite positive

2 (4%)

2 (4%)

Both positive

0 (4%)

2 (4%)

Leukocyte negative

6 (11%)

1 (2%)

Nitrite negative

10 (19%)

39 (73%)

Both negative

4 (8%)

1 (2%)

(4) Pyuria

(5) ATP*

(6) IB*

 

Culture positive

Culture negative

 

Culture positive

Culture negative

 

Culture positive

Culture negative

Pyuria positive

9 (17%)

35 (66%)

ATP >50 nmol/l

3 (6%)

0 (0%)

IB positive

1 (2%)

22 (41%)

Pyuria negative

3 (6%)

6 (11%)

ATP <50 nmol/l

9 (17%)

41 (77%)

IB negative

11 (21%)

19 (36%)

(7) Combined ATP and IB**

      
 

Culture positive

Culture negative

      

ATP >50, IB positive

1 (2%)

0 (0%)

      

ATP <50, IB negative

0 (0%)

18 (34%)

      
  1. *denotes Fisher’s exact test <0.05. **denotes Fisher’s exact test =0.0556 (not quite significant). See Methods for an explanation of the surrogate markers used. Key: IB, intracellular bacteria.
  2. Data not included in the contingency tables: with respect to combined dipstick tests; 6 patients (10%) were leukocyte positive/nitrite negative and culture positive; 37 patients (70%) were leukocyte positive/nitrite negative and culture negative; 2 patients (4%) where leukocyte negative/nitrite positive and culture positive; 1 patient (2%) was where leukocyte negative/nitrite positive and culture negative. With respect to combined ATP and IB; 9 patients (17%) were IB positive/ATP <50 and culture positive; 22 patients (41%) were IB positive/ATP <50 and culture negative; 3 patients (6%) were IB negative/ATP >50 and culture positive; 0 patients were IB negative/ATP >50 and culture negative.