fetal maturity testing


Fetal Tek 200 L/S Procedure

fetal tek 200













Respiratory Distress Syndrome (RDS) is a great concern in premature births, and occasionally occurs in full term infants. The breathing difficulty in RDS may be caused by lack of alveolar stability and may result in death from hyaline membrane disease.

Since introduction of Gluck's two-dimensional thin layer chromatographic procedure in 1971, the L/S ratio has gained acceptance as an important element in estimating fetal lung maturity. L/S ratio values, as related to fetal lung maturity, are divided into three categories: immature, transitional and mature. No exact borders exist between the phases, and test results must be interpreted carefully.

Fetal-Tek 200 is an excellent one-dimensional TLC technique for separating lecithin and sphingomyelin. The sample extract is applied as a band across the channel of the TLC plate. Separation occurs in a solvent system of chloroform, methanol, triethylamine, 2-propanol and water. The longer plate and improved solvent system give excellent separation of lecithin and sphingomyelin away from other phospholipids and neutral lipids contained in amniotic fluid. Charring is achieved using phosphoric acid with a cupric acetate catalyst, a much easier system to handle than sulfuric acid. The L/S ratio is determined using a scanning densitometer such as the Helena QuickScan 2000.


Fetal-Tek 200 Equipment Kit

Cat. No. 8022

- Fetal-Tek 200 Equipment Kit
- Fetal-Tek 200 Developing Chamber (Cat. No. 8024),
- 1/pkg Micropreparation Dish (Cat. No. 8003), 1 pkg
--25 mL Dialamatic Microdispenser and Tubes
(Cat. No. 6225), 1dispenser, 100 tubes -
- Fetal-Tek 200 Wicks (Cat. No. 8023), 50/pkg
- Fetal-Tek 200 Marker (Cat. No. 8026), 1 x 1 mL
- Fetal-Tek 200 TLC Plates (Cat. No. 8028), 10/pkg
- Fetal-Tek 200 Control Combination Package
(Cat. No. 8033), 10 x 5 mL each level
- Fetal-Tek Spray Caps (Cat. No. 8001), 3/pkg
- Cupric Acetate (Cat. No. 8000), 3 x 250 mL










Fetal Tek Supplies

Fetal-Tek 200 L/S TLC Plates

  • protein c
Cat. No. Item
8028 Fetal-Tek 200 TLC Plates (10/pkg), 10 x 20 cm

The plate is a specially formulated silica gel on glass. A pre-adsorbent layer at the bottom of the plate aids in maintaining fraction integrity. The material for these plates has been carefully selected to ensure proper lipid separation. Each plate is 10 x 20 cm.


Fetal-Tek 200 L/S Controls

  • protein c
Cat. No. Item
8033 Combination Control Kit (3 levels), 30 x 5 mL
8030 Immature Control, 10 x 5 mL
8031 Borderline Control, 10 x 5 mL-
8032 Mature Control, 10 x 5 mL

All controls contain lecithin and sphingomyelin. Borderline control also contains phosphatidylinositol and Mature control also contains phosphatidylinositol, phosphatidylglycerol and phosphatidylethanolamine. These extractable controls are treated the same as patient amniotic fluids, providing verification of all phases of the procedure. Reconstituted controls are stable 5 days at 2 to 6-C. Combination Kit (Cat. No. 8033) contains 10 vials each of Immature, Borderline and Mature Controls (30 vials total).


Fetal-Tek 200 Marker

  • protein c
Cat. No. Item
8026 Fetal-Tek 200 Marker, 1 x 1 mL

The Fetal-Tek 200 Marker is for use with the Fetal-Tek 200 procedure for identification of the lecithin, sphingomyelin, PG, PI and PE bands. Along with the Fetal-Tek 200 Controls, the marker is very useful in determining the sources of procedural problems. The marker is a stabilized chloroform solution which is used without extraction.


Fetal-Tek 200 Developing Chamber

  • protein c
Cat. No. Item
8024 -Fetal-Tek 200 Developing Chamber, 1/pkg

The Fetal-Tek 200 Developing Chamber is specifically designed to accommodate the Fetal-Tek 200 plate and wick. The glass cylinder is 23 cm tall with an outside diameter of 11 cm. The plastic lid is designed to retain vapors and assure maximum chamber saturation during migration.


Cupric Acetate

  • protein c
Cat. No. Item
8000 -Cupric Acetate - Liquid, 3 x 250 mL

Cupric Acetate is recommended for staining Fetal-Tek 200 L/S Ratio TLC plates. The liquid stain contains 3% (w/v) cupric acetate in 8% (v/v) phosphoric acid.


Fetal-Tek Spray Caps

  • protein c
Cat. No. Item
8001 -Fetal-Tek Spray Caps, 3/pkg

The spray caps fit on the Cupric Acetate bottles for convenient delivery of the stain to the TLC plate. Spray caps are reusable.


Micropreparation Dish for Fetal-Tek 200

  • protein c
Cat. No. Item
8003 -Micropreparation Dish, 1/pkg

The Micropreparation Dish is made of nylon and can be used to concentrate almost any solvent. It is ideal for simultaneously concentrating up to eight, 1 mL chloroform extracts in the Fetal-Tek 200 procedure. The lip around each sample well deters spillage and cross contamination. The conical shape of the well assures concentration of the phospholipids into a small area, thus allowing use of very small amounts of chloroform to apply samples for TLC.