Comparison of conventional guaiac to four immunochemical methods for fecal occult blood testing: implications for clinical practice in hospital and outpatient settings.
BACKGROUND
Fecal occult blood testing (FOBT) is one method to screen for colorectal cancer and to assess for gastrointestinal bleeding in hospitalized patients. Differences in the analytical sensitivity among various methods may have significant clinical repercussions.


METHODS
We evaluated the analytical performance of 5 different FOBT methods (standard guaiac-based method and four immunochemical methods) using patient samples and spiked stool specimens.


RESULTS
The analytical sensitivity measured using spiked stool samples varied from <8 to 1500 ug hemoglobin/gram of stool. In some cases the results differed significantly from the manufacturers reported analytical sensitivity. Analysis of 71 stool samples measured by all 5 methods showed a discrepant result in 31 cases (43.7%). The rate of positive samples varied by method from 8.5% to 42.2%.


CONCLUSIONS
These results demonstrate significant differences in the analytical performance among FOBT methods. Careful method validation and selection of a method with appropriate sensitivity is essential when choosing an FOBT method for colorectal cancer screening or for the assessment of gastrointestinal bleeding in the emergency department and hospital inpatients.
Tannous
Bakhos
B
Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, United States.
Lee-Lewandrowski
Elizabeth
E
Sharples
Cyrrene
C
Brugge
William
W
Bigatello
Luca
L
Thompson
Taylor
T
Benzer
Theodore
T
Lewandrowski
Kent
K
D000553:Ambulatory Care; D019963:Clinical Chemistry Tests / Q000379:methods*; D003113:Colonoscopy; D005500:Follow-Up Studies; D006471:Gastrointestinal Hemorrhage / Q000175:diagnosis; D006138:Guaiac; D006761:Hospitals; D006801:Humans; D007120:Immunochemistry; D009780:Occult Blood; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D006138:Guaiac