Use of fluorescein labelled antibody and fluorescence activated cell sorter for rapid identification of Mycobacterium species.

A fluorescein labelled antibody (Ab)/Fluorescence Activated Cell Sorter (FACS)-based assay was developed for detection of a wide range of mycobacterial species directly from bacterial culture and sputum specimens. The whole process could be completed within 3 hours and had a high specificity and sensitivity for cultured bacteria. The method was also shown to be applicable for direct identification from clinical specimens. This study showed that pretesting of clinical specimens for mycobacteria to the genus level with an antibody to Mycobacterium species offers the routine clinical laboratory a single convenient test for the detection of tuberculous and nontuberculous mycobacteria. Depending on the availability of species-specific antibody, the identification of Mycobacterium to the species level can be achieved.

The significance of abnormally high and low maternal serum alpha-fetoprotein levels between 14 and 25 weeks of gestation.

A total of 6,160 gravidas with gestational ages from 14 to 25 weeks were collected to quantify maternal serum alpha-fetoprotein (MSAFP) using an enzyme immunoassay kit. A level over 2.5 MoM (multiples of the median) was defined as high and a level below 0.4 MoM as low. Ninety-eight women (1.59%) had an initially high MSAFP and 88 (1.42%) a low MSAFP. In the low MSAFP group, 80% returned for a further checkup. Among them, 46% had an over-estimation of gestational age based on their last menstrual period (LMP), 28% had a normal MSAFP and 9% still had a low MSAFP level on a repeat test. Pathologic conditions in other pregnancies included a hydatidiform mole, miscarriage and pseudocyesis. One nonresponder had an ectopic pregnancy. After delivery, no major fetal abnormalities, including trisomy syndromes, were noted in pregnancies carried to term. In the high MSAFP group, 84% returned for check-up. Among them, 15% had an under-estimation of gestational age based on LMP, 16% had twin pregnancies, 46% had a normal MSAFP and 12% still had a high MSAFP on a repeat test. Pathologic conditions in the other pregnancies included one anencephaly, one hydrocephaly and 6 miscarriages. Wrong dating by LMP and false positivity were the most frequent causes of abnormal levels of MSAFP. Two gravidas had artificial abortions because of undue anxiety. MSAFP screening in Taiwan for open neural tube defects does not seem appropriate and using 0.4 MoM as a fixed low cut-off point is inadequate for trisomy syndrome screening. Maternal anxiety should be seriously considered and proper genetic counseling implemented in a screening procedure.