TABLE 5.
Effect of delayed plating of urine specimens preserved in boric acid solutionsa
| Study (reference)b | Preservative(s) | Preservative used for immediate culture | No. of h that culture was delayed (preservative[s]) | Threshold (no. of CFU/ml) | NSG present |
SG present |
||
|---|---|---|---|---|---|---|---|---|
| No. of specimens subjected to immediate culture | % change from no. after delay | No. of specimens subjected to immediate culture | % change from no. after delay | |||||
| Southern and Luttrell (36) | GBF | GBF | 24 (GBF) | >5 × 104 | 180 | −17.8 | 8 | +500.0 |
| Lum and Meers (31) | BA | GBF | 24 (GBF) | >105 | 146 | −2.1 | 29 | +10.3 |
| Wright et al. (32) | BA, GBF, SBF | None (fresh specimens were used) | 24 (BA, GBF, SBF) | >105 | 193 | −7.3 | ||
| Weinstein (37) | GBF, SBF | GBF | 24 (GBF) | ≥105 | 763 | +1.2b | 106 | −8.5b |
| Hubbard et al. (34) | GBF | GBF | 24 (GBF) | >105 | 75 | +4.0 | 25 | −12.0 |
| Porter and Brodie (28) | BA | BA | 72 (BA) | >105 | 112 | 0 | 18 | 0 |
a
GBF, glycerol-boric acid-formate; BA, boric acid; SBF, sorbitol-boric acid-formate; NSG, nonsignificant growth; SG, significant growth. All studies were given a quality rating of fair.
b
There were 7 fewer patient samples available for analysis with delayed culture (862 patient pairs versus 869); the percent increase was calculated assuming 869 pairs.