Maintaining long-term stability of analytical procedures is an important responsibility for clinical laboratories. This process typically includes a comparison of current and new reagent lots through paired measurements of patient or control samples, with defined criteria for acceptance and rejection of the new lot.

This is the September 2013 issue of Clinical Chemistry: Volume 59, Issue 9.

On the cover this month: A pregnant woman with a flower blossom on her glowing belly. Pregnancy should be a time of joy and anticipation. Although most pregnancies progress without major complications, one medically important complication is gestational diabetes, a condition associated with adverse outcomes for both the mother and fetus. The prevalence of gestational diabetes is increasing in parallel with the prevalence of obesity and type 2 diabetes. Will more efficient and more scientifically based approaches to diagnosis and treatment keep up with the added demands on healthcare systems? In this issue of Clinical Chemistry, Coustan provides readers with an overview of current controversies as well as current recommendations for gestational diabetes care.

MicroRNAs are present in body fluids and have the potential to serve as disease biomarkers. A study in the April 2013 issue of Clinical Chemistry explored the clinical value of microRNAs in serum and urine as biomarkers for idiopathic childhood nephrotic syndrome.

Pregnant women identified as high risk based on the

prenatal screen can then undergo invasive procedures such

as amniocentesis to confirm the diagnosis. Unfortunately, a

large number of women with unaffected pregnancies

undergo invasive procedures, putting the fetus at

unnecessary risk for miscarriage.

Maintaining long-term stability of analytical procedures is an important undertaking for clinical laboratories. This process typically includes comparison of current and new reagent lots through paired measurement of patient and control samples, with defined criteria for acceptance and rejection of the new lot.

Personalized medicine implies that an individual's

unique genetic makeup provides key information to guide

prevention, diagnosis, and treatment of disease. It's highly

probable that no one besides yourself has ever been born or

ever will be again with your precise DNA sequence, unless

you are an identical twin and even then maybe not.

August 2013 Audio Summary

The US Food and Drug Administration has long maintained its right to regulate LDTs; however until recently they've chosen to exercise discretion and have left this to the individual laboratories and other regulatory agencies. This is now in a state of change, and the FDA has stated that it would issue guidance on its oversight of Laboratory Developed Tests.

Prenatal development involves a series of highly-organized genetic and epigenetic events. Abnormalities in the epigenetic control of developmental processes have been implicated in infertility, spontaneous abortion, intra-uterine growth abnormalities, and numerous post-natal consequences.

Human growth hormone is an important peptide hormone that stimulates growth, cell reproduction, and cell regeneration. Measuring growth hormone in the blood is an important clinical assay, but may be problematic due to heterogeneity of the hormone that may arise from alternative splicing, different post-translational or modifications, oligomerization, formation of complexes, and proteolytic processing. Although standards for growth hormone are available, data from external quality assessment programs show large differences exist between measurement results obtained with different assays.