Abstract:
Delay in transport of urine specimens from
collec-tion site to analytical laboratories causes significant
errors. Preservatives conserve the characteristics of the
urine. The objective of the study was to compare the effect
of different preservations on pH, glucose and protein in
urine. Collected urine samples from normal individuals
were aliquoted for different preservation methods after
adding glucose (20, 40, 60, 80, 100 mg/dL) and albumin (20,
30, 100, 300, 500 mg/dL) and stored for 0, 6, 24, 48 and 72
hours. The pH, glucose and protein were measured using
pH meter, glucose oxidase, sulfosalicyclic acid methods
respectively. Urine samples stored without preservatives
showed statistically significant differences (p<0.05) for
pH, glucose and protein at 6 hours with 0 hour sample.
The pH of urine samples stored at 4°C showed significant
differences at 72 hours (p<0.05). Added glucose (20 mg/
dL) and added protein (20 mg/dL) of urine samples
stored at 4°C showed significant difference at 24 hours
(p<0.05). Urine samples with 40, 60, 80 and 100 mg/
dL ‘added’ glucose and those with 30, 100, 300 and 500
mg/dL ‘added’ protein stored at 4°C showed significant
differences at 6 hours (p<0.05). Urine samples stored at
25°C with thymol or toluene showed significant differences
at 6 hours (p<0.05) for pH, glucose and protein. Urine
samples without preservatives showed significant dif ferences when compared with urine samples at 4°C, either
with thymol or toluene (p<0.05). Urine samples stored at
4°C showed significant differences when compared with
urine samples either with thymol or toluene (p<0.05). Urine
samples with thymol showed no significant differences
for pH (p>0.05) while showing significant differences in
glucose and protein when compared with urine samples
with tolu-ene (p<0.05). The preservation of the urine
samples at 4°C is superior to the chemical preservatives
and without pre-servatives. If refrigeration is unavailable,
then it is recom-mended to use either toluene or thymol.
Among the two preservatives, toluene is better to preserve
glucose and thy-mol is better to preserve protein. Thymol
has strong anti-bacterial attributes whereas toluene acts
as a physical bar-rier to air and bacteria.
