1. How long will it take to get my results?
- The typical turnaround time for most assays is ~3 weeks. We process all requests in the order in which they are received so large preceding requests or unexpected problems with an assay can cause delays.
- Low-frequency assays are only run when we have a sufficient number of samples to cover the cost of the assay.
2. Can I request expedited service?
- Although it's helpful for us to know when results are needed urgently, we process all requests in the order in which they are received.
3. Can I get a discount for submitting a large number of samples?
- No, the lab is a federally supported non-profit core, therefore assays are already performed at cost.
4. How much sample is required for the assay?
- See here.
5. What is the range of detection of the assay?
- See here.
6. Can I submit one tube for multiple assays?
- No, to avoid multiple freeze/thaw cycles samples must be aliquoted into separate tubes for each assay.
7. Can I submit serum instead of plasma?
- Yes, but plasma is preferred because it is cleaner, easier to work with, and therefore gives better results.
8. Where do I drop off / send my samples?
- See here. Please ship overnight, Mon-Weds, with sufficient dry ice to avoid loss of your sample.
9. Do I need to add a preservative during sample collection?
- It depends on the analyte.
10. What factor converts insulin from µU/ml to pmol/L or ng/ml?
- 1 µU/ml = 6 pmol/L
- 1 µU/ml = 0.04 ng/ml
11. What factor converts glucagon from pg/ml to pmol/l?
- Divide pg/ml by 3.45 to convert to pmol/l.
12. I'm having trouble with iLab, what should I do?
- See here.
13. iLab is asking for a PO number. I don't have one yet, what should I do?
- See here.
14. What does it mean if my samples are off the curve?
- Results can only be considered valid if they are on the standard curve of the assay. If samples are too concentrated they need to be diluted with the appropriate buffer (contact the core) and resubmitted for analysis via iLab.
- RIA standard curves are sigmoidal, therefore the most robust and reliable part of the curve is at the assay's ED50. Reduced accuracy and precision, leading to greater variability, occurs at the upper and lower tails of the curve. Your RIA data will include the ED50 of that assay, the % binding of each sample (50% is at the ED50), and the % binding range of the standard curve. CVs are calculated from the measured radioactive counts (cpms) of the sample duplicates, which are the best reflection of how the assay performed since they are influenced by factors within the control of the core (e.g. accurate pipetting etc), rather than from % binding, where the magnitude of variability is heavily influenced by the concentration of the sample.
15. What is the best way to collect mouse blood?
There are several ways to achieve this goal:
heparinizing the syringe (ideal for heart stick).
using EDTA coated commercial collecting tubes, e.g. Sarstedt (ideal for tail vein collection).
homemade EDTA evaporated tubes (often used for draws through catheters with blunts) - add 20 uL of 100 mM EDTA pH 7.4 in 0.5 mL tubes and air dry (evaporation will take a couple of days).
16. What evidence is there that hemolysis will affect my results?
- Hemolysis is a major cause of variability in insulin measurement during oral glucose tolerance test in children
- Hemolysis Affects C-Peptide Immunoassay
- Effect of hemolysis on the concentration of insulin in serum determined by RIA and IRMA
- Hemolysis Interference: Are Laboratories Getting the Information They Need?
17. The status of my iLab request is "Waiting for Financial Approval." What does this mean and what do I need to do?
- When service requests are submitted to core facilities by members of a lab, there may be times when the request requires financial approval. In most cases, this approval step is triggered when the quoted cost of the service exceeds the amount the lab member is auto-approved to spend per the lab's auto-approval settings. The PI of the lab must approve the request via iLab in order for the analysis to proceed.
- To avoid this requirement the PI can raise the threshold on the total allowable amount a lab member is allowed to order on a per order basis without PI approval.
18. Which catecholamines can be measured and how should samples be processed?
- Epinephrine and norepinephrine (not dopamine). EGTA-glutathione must be added at the time of collection! The core does not process tissues but procedures are available.
19. Can catecholamines be measured in samples in which EGTA-glutathione was not added?
- We do not recommend it. If the samples were protected from light, quickly frozen after sampling, recently taken, and stored at -70 C they may be ok, but we have no way of predicting how those variables may affect your results.
20. Does the Hormone and Analytical Services Core measure lipids?
- No, this analysis is done by the VUMC Lipid Core.
21. Where can I find my results?
- When your request is completed you will receive an automated email from iLab containing a link to your request. To find your request make sure that you have selected to display 'completed' rather than 'active' requests. Your data will be in a file in the "Attachments & URLs" section of the request. For example:
22. Why am I getting a "Validation failed" error when placing a request?
- VUMC Cores must manually assign pricing for new external users. If you get this error email Dale Edgerton. Price assignment usually takes several days to process.
23. Can I pay by credit card?
- No. See here for approved payment methods.
24. When will I be billed? Can I pay early since I have expiring funds?
- VUMC sends invoices the month after services are completed. Please submit the invoice to your Procurement Office requesting payment as per the “Remit Payment To” instructions on the invoice. It is not possible to pay prior to receiving the invoice.
25. I need a quote. How can I get one?
- Place a request in iLab then contact the lab. We will then generate a quote for you from the request. If you only need the quote and are not actually ready to submit samples let us know and we will cancel the request after generating the quote.
***This core is supported by NIH grants DK059637 (MMPC) and DK020593 (DRTC). Please include an acknowledgment in your publications.***