Specimens collected from WHI participants are maintained in a biorepository in Rockville, MD. The sample inventory is tracked via a WHI Specimen Tracking database, which includes variables associated with the specimens, such as number of fasting hours before blood draw, extraction and quantitation method, and number of freeze/thaw cycles. All biospecimens collected from WHI participants are available for use by Ancillary Studies (ASs) based on scientific merit. To access WHI biospecimens, investigators must have an approved and funded ancillary study. See our Propose a Study page for details.
Participants were asked to fast for at least 12 hours before blood draws. In some cases participants were not fasting. Fasting status is indicated in the database.
All specimens described below are stored frozen at -80 degrees Celsius at a central repository in Rockville, MD. Specimen processing for ancillary studies (aliquoting, DNA extraction) occurs in a central lab (FHCRC specimen processing lab [SPL]).
Serum, plasma (EDTA, citrate), RBCs, and urine samples are stored in 1.8 ml parent vials or 0.25 ml subs. When parent vials are accessed, an aliquot is made for the testing lab and the remaining volume is placed into 0.25 ml subs for storage at the WHI repository. All samples will have undergone at least one freeze/thaw before they arrive at the testing lab. Freeze/thaw cycle is captured in our database.
In 2009/2010, samples from <= 3% WHI RBC draws suffered degradation as the result of storage at -20 degrees Celsius while at the processing lab for aliquoting (as described by Pottala et al., Lipids 2012). The affected vials have been removed from the WHI biorepository inventory. Two RBC processing procedures have since been implemented to prevent RBC sample degradation: (1) RBC samples are consistently stored at -80 degrees Celsius, and (2) the minimum RBC aliquot volume is 250 ul (to prevent oxidation). With these procedural changes, the WHI RBC samples are of good quality for use in ancillary studies.
Buffy coat is stored frozen in our repository and DNA is extracted from the stored buffy coat when it is requested for an ancillary study. An aliquot is made for the testing lab and the remaining sample is returned to the WHI repository.
DNA has been extracted using different methods over time.
The current "Five Prime" extraction method was developed by FHCRC using Qiagen reagents in a method designed to maximize both the quality and yield of extracted DNA. An AS may receive DNA samples extracted by different methods in the past, as well as freshly extracted DNA. Extraction method is tracked in the WHI specimen database. Please note that the DNA is extracted on an "as needed" basis, so the date of extraction does not correlate with the date of the blood draw. All Long Life Study DNA has already been extracted using the Five Prime method.
DNA concentration is assessed at the time of extraction. DNA concentration was first assessed using spectrophotometry. Starting in August 2007, DNA concentration has been assessed using PicoGreen. Concentration method is tracked in the WHI specimen database.
A PAXgene tube was collected during the Long Life Study visit. RNA/miRNA was extracted from the PAXgene tube within ~1 month of collection. The concentration of RNA was determined by NanoDrop. The extracted RNA is stored frozen in the WHI repository.
Parsimonious use of specimen is an important consideration in review of AS proposals. Without significant scientific justification, ancillary studies are limited to the following samples volumes (including any necessary "dead volume", or padding) from a given specimen collection time point:
Samples are available for almost all study participants, though for some outcomes particular sample types may be more limited. Investigators working on ancillary study proposals can use the WHI Query Builder, a website that lets users create ad-hoc queries that return the number of WHI participants with various criteria, including specimen availability. For Query Builder access, please contact the WHI Help Desk (email@example.com).
Pooled samples of serum, citrated and EDTA plasma were created close to the start of WHI enrollment to be tested for core analytes and CVD biomarkers alongside participant samples. Results from these samples allow the Lab Working Group to monitor the stability of primary analytes over time.
WHI uses blood samples from women who consented to the screening blood draw, but were not enrolled or randomized into any WHI component. The samples are relabeled to provide blinded duplicate samples that are included in all batches of assays. When preparing budgets, please include the costs for testing the blind duplicates. There is no covariate data associated with these samples.
WHI includes blind duplicates as quality control samples in all sample pulls, as follows:
The adequacy of serum and plasma aliquoting by the Specimen Processing Lab is evaluated by testing a subaliquot from each blind quality control sample for total cholesterol. Similarly, urine samples are tested for sodium. The correlation and average CV% between the members of each blind pair is computed and reviewed by the WHI Lab Working Group.
Contact the WHI Help Desk at firstname.lastname@example.org if you need assistance or have questions.