FAQ

1. Where can I get a quick guide to the HOMA model?

30-Jun-2004
The "Use and Abuse of HOMA modeling" paper [Wallace TM, Levy JC, Matthews DR. Diabetes Care (2004); 27(6): 1487-95] addresses most HOMA issues. Additional HOMA related papers are listed in publications.

2. What input values will the HOMA Calculator accept?

30-Jun-2004
As HOMA is a steady state model, only clinically realistic values that would be seen in a fasting subject should be used. These are:

• Plasma glucose 3.5 to 25.0 mmol/L
• Plasma insulin 20 to 400 pmol/L
• Plasma specific insulin 20 to 300 pmol/L
• Plasma C-peptide 0.2 to 3.5 nmol/L

3. Why does the Excel version give errors for some input values?

30-Jun-2004
Outside the accepted range (see Q2) calculation is often impossible. The Excel version gives an answer wherever possible but answers outside the accepted input range should be treated with caution.

4. I'm getting an error 'Run Time Error "13", Type Mismatch'?

30-Jun-2004
This problem is resolved in version 2.2 and above. Please download the latest version.

5. I am having problems downloading the HOMA Calculator

30-Jun-2004
There are known IE problems associated with some web browsers. You can overcome these by following the instructions given below:

• Go to our website http://www.dtu.ox.ac.uk/homacalculator/download.php
• Right click and let go on the 'Windows' link under the ‘Download the HOMA Calculator’ heading.
• Select 'Save target as...' from the menu that pops up.
• Select a location for the file- use desktop for now to keep things simple – and save.
• Close Internet Explorer and all other applications.
• There should be an Icon on the desktop called ' HOMA2CalculatorSetup.exe'.
• Double click this icon.

6. I have downloaded and installed the HOMA Calculator but it will not work.

01-Jun-2004
You must ensure that you have administrator rights on your computer. Please query this with your IT department. Typically you may see the following messages

• -2147024770 automation error
• Code: 429 active X component can’t create object
• Setup fatal error: unable to generate installation log file

7. Why does the HOMA Calculator return 'Unable to calculate' for certain input values?

13-Jul-2011
The HOMA calculator is not running a simple equation to produce its answers. It is instead running very complex mathematical model of the human body. In order to produce the answers it chooses a starting point based upon the inputs value provided. It then iterates the model until it converges on the correct answer. Sometimes the model will not converge. Changing the inputs very very slightly will often change the starting parameters used for the model. This can lead to the model then being able to converge correctly and provide a working answer.

Our suggestion is to change the input values slightly below the actual value and then slightly above the actual value and check that the results returned are comparable.

8. I downloaded the HOMA calculator for Excel, when I try to open it and enter data I get an error message?

21-Oct-2011
Currently the installation program for HOMA Calculator for Excel places a file called HOMACore.dll in the HOMA folder at the root of the C drive. If you move this file after installation then the calculator will stop working. Re-instalation of the the program should solve the problem. It is also worth pointing out that the software must be installed on each machine you are going to use the Excel workbook on. Although you cannot move the HOMACore.dll you may copy, move or rename the Excel workbook that is used to perform the calculations.

9. Mac OS X 10.7, Lion support?

16-Apr-2012
A new version of the HOMA Calcualtor is being prepared that will be compatible with Mac OS X 10.7, Lion.

10. Problem using the HOMA calculator with Office 2010 64bit

02-Jan-2012
We are aware that the current version of the HOMA calcualtor does not work with Office 2010 64bit. A new version of the HOMA calculator will be required to solve this problem. In the mean time using the 32bit version of Office 2010 on 64bit windows works fine and will calculate the results correctly. Please uninstall Office 2010 and reinstall it, selecting the option for 32bit version as required. This should not interfere with other uses of Office.

OCDEM, Churchill Hospital, Old Road, Headington, Oxford, OX3 7LJ
Tel: +44 (0)1865 857233   Fax: +44 (0)1865 857235     Email: homa.calculator@dtu.ox.ac.uk

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