The steatocrit is rapid method to estimate the amount of fat excretion in the stool. It is similar to the capillary hematocrit and is considerably more convenient than a conventional 72 hour stool analysis. It can be used to monitor a patient's response to therapy.
Method:
(1) 0.5 grams of feces from a spot collection are mixed with 2 mL of water and 0.06 grams of sand. The mixture is then homogenized in a blender.
(2) The slurry is placed in a 75 mm heparinized microhematocrit tube with the end sealed with wax.
(3) The tube was centrifuged at 12,000 prm for 15 minutes in microfuge.
(4) The layers of fat and solid material are then measured in mm.
NOTE: This method does not use acid to extract the fat, as is done in acid steatocrit (above).
percent fat =
= (length of fat layer) / ((length of fat layer) + (length of solid layer)) * 100%.
Guarino found that for children (maximum age 15 years) the steatocrit correlated with quantitative fecal fat analysis (Van de Kramer) as:
fecal fat in grams per 24 hours =
= (0.1939 * (steatocrit in percent as a whole number)) – 0.2174
which is derived by rearranging the equation for Figure 1 on page 270.
The steatocrit is higher in infants and dropped with age (Figure 2, page 271).
|
Age in Months |
Upper Limit (mean + 2 SD) for Steatocrit in Normal Children |
|
0 |
19.5% |
|
5 |
9.6% |
|
10 |
7.8% |
|
15 |
6.7% |
|
20 |
5.8% |
|
25 |
5.1% |
|
30 |
4.6% |
|
35 |
4.3% |
|
40 |
3.8% |
|
45 |
3.5% |
|
50+ |
3.2% |
The line for 5 to 50 months can be estimated as:
percent fat (as a whole number) =
= (-0.000085 * ((age in months)^3)) + (0.01 * ((age)^2)) - (0.04564 * (age)) + 11.57
A steatocrit greater than the upper limit as abnormal.
The steatocrit may be reported as a multiple of the upper limit of normal for the age-matched control.
Performance:
• Levels of fat recovered by the steatocrit method are less than those seen with the acid steatocrit.
Specialty: Gastroenterology, Nutrition
ICD-10: ,
