Lectithin – to – sphingo myelin ratio

Sample type

Serum

Uses

1-Traditional biochemical test to measure fetal lung maturity

Precautions

we recommend drawing the specimen before initiation of immunosuppressant medication

Interferring factor

1-Blood and meconium contamination can affect result

2-Definite exceptions to prediction of pulmonary maturity with L:S ratio >2.0

• Infant of a diabetic mother (L:S ratio >2.0 has been frequently seen in cases in which RDS developed)

• Erythroblastosis fetalis

3-Possible exceptions

• Intrauterine growth 2-retardation

• Toxemia of pregnancy

• Hydrops fetalis

• Placental disease

• Abruptio placentae

Pre analytical errors

1. 1 hemolytic disease of new born affect the result

Corrective action

the history of the new born should be taken correctly from parent

Post-analytical errors

1- Write another patient’s name on the report

The corrective action

Make sure you write the correct name on the report

2-Writing a wrong result in the report

The corrective action

If the report is not delivered to the patient and this error is discovered the correct result must be written, but if the report is delivered to the patient, must communicate with him and tell him that an error has occurred and replace the report with the report in which there is the correct result

3-If laboratory specialist make mistakes in equation this affect the result

Corrective action

We should be careful in calculations and review them more than time

Reference range

2.0 to 2.5