[Influence of the pre-analytical specimen storage conditions on the fecal occult blood test results].
BACKGROUND
Korean national cancer screening program selected fecal occult blood test (FOBT) as a primary screening method of colorectal carcinoma in adult > or =50 yr old irrespective of symptom. Notice to pre-analytical errors is especially important for the FOBT because examinees collect and submit their specimens to laboratories by themselves. We examined the influences of the fecal storage temperatures, durations and with or without buffer on the FOBT results.


METHODS
Thirty FOBT-positive specimens above 100 ng/mL were used for the study from July to August 2008. Quantitative FOBT was performed with OC-sensors II (Eiken Chemical Co., Japan). Each specimen was divided into 4 groups. Two groups in plastic buffer-free containers were kept either at 4 degrees C or room temperature (25-28 degrees C), respectively. Another two groups in buffer-tubes were also kept either at 4 degrees C or room temperature. Each group was repeatedly examined with same method every 24 hr up to 120 hr.


RESULTS
Eleven specimens (36.7%) in buffer-free containers converted to negative results (below the 100 ng/mL) after 24 hr and 17 specimens (56.7%) did after 48 hr at room temperature. Ten specimens (33.3%) in buffer-free containers converted to negative after 48 hr at 4 degrees C. Specimens contained in buffer-tubes showed little change; 3 specimens (10.0%) at room temperature and no specimen at 4 degrees C showed negative conversions after 48 hr.


CONCLUSIONS
Buffer-tube minimizes false negative FOBT results during pre-analytical delay of specimen. The examinees using buffer-free containers need to be educated to hand in their specimens to laboratories as soon as possible.
Yoo
Soo Jin
SJ
Department of Laboratory Medicine, Sanggye Paik Hospital, Inje University College of Medicine, Nowon-Gu, Seoul, Korea.
Moon
Se Jin
SJ
Gwack
Eun Hye
EH
Shin
Bo Moon
BM
D002021:Buffers; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D006801:Humans; D008875:Middle Aged; D009780:Occult Blood; D013048:Specimen Handling; D013696:Temperature; D013997:Time Factors
D002021:Buffers