First Trimester Prenatal Diagnosis

Always contact laboratory prior to sampling

The laboratory should always be contacted prior to prenatal sampling. Direct analysis of uncultured chorionic villus is not universally appropriate, also, for some disorders, prenatal diagnosis is not yet available. It is important that biochemical diagnosis has been established in the proband and if this has not been done in this laboratory, it may be necessary to confirm the diagnosis on a fresh sample or to verify a diagnosis made elsewhere before accepting the sample. It may also be necessary to study enzyme activities in parents/obligate heterozygotes prior to prenatal studies. We would be happy to provide advice on appropriate samples for each condition, the amount required and the best gestational age for sampling. We do not charge for advice given over the telephone, so please contact us with any clinical or technical enquiries.

The charge for prenatal diagnosis by direct analysis of chorionic villi or cultured amniotic fluid cells is as quoted for each specific test plus an additional £55.14. Where cultured amniocytes or cultured chorionic villus cells are required, the appropriate culture charge must be added.

Test Required specimen & volume Special precautions Turnaround time Reference ranges Section
First trimester prenatal diagnosis* CVS, cell free amniotic fluid, cultured cells To be transported in culture medium, at room temperature and to reach the laboratory within 72 hours of sampling Dependent on assay needed. Up to 2 working weeks. Many assays will be within 5 working days of receipt. Check with lab for reporting time expected for individual assays. Dependent on analysis. Control values included in the analysis are quoted. Various

* All samples must be accompanied by relevant clinical details. This is particularly imperative for urine amino acids, urine organic acids, urine mucopolysaccharides and all samples for prenatal diagnosis. Reports may be withheld where samples are received without clinical details as an accurate interpretation may not be possible without them.