So, despite your best care, or maybe just for a well bird check, you go to the vet's office. Different tests that should be done are explained here, for a Well bird Check. One of the first tests a vet will do is the CBC. This can show different things depending on the given situation. There are many sites on the internet that explain what a CBC includes, one of which can be found at Complete Blood Count and also a set of normal values for most birds can be found here.

  The thing I found pressing to do here,  was to explain the conversion difference between the Canadian Values, which uses the SI units (International System of Units) and the US where it is mostly Conventional Units still used. Since most of the normal value charts that you will find on the internet, come out of US labs, a quick glance will lead you to believe your bird is very sick.
Here is how the conversions look and are done.

(examples used are for African Greys from California Avian Lab 1996)
WBC- 6-13 This, although using slightly different formulas,  will be the same result in SI units as in the US measurement.

PCV- 42-52% US uses % and SI units use decimal so this would look like .42-.52 SI

Het/Neut- 45-72 This is a percent in both forms so is not affected by the different methods.

Lympho- 20-50 Again, just a percent

Mono-0-1 Percent again

Basoph- 0-1 Percent again

Eosino-  0-1 Percent again

PP- 3.2-4.5 US measures use g/dl, in SI units it is g/L making it 32-45 (x10 of US measure)

SGOT- 112-339 IU/L   SI uses the same units

CPK- 120-410 IU/L  Again, same units

Uric- 1.9-9.7mg/dl. In SI units this is measured as umol/L so to come up with our number you use a conversion factor of x 59.48  113- 577 umol/L. If you have SI units and want to convert to the US units  x .0168

Calc- 8.3-11.7 mg/dl. In SI units this is measured as mmol/L. Conversion factor is x 0.25
2.07-2.925mmol/L . To convert from the SI to the US units x 4.

Glucose - 280-354 mg/dl . In SI this is measured as mmol/L. conversion factor is x .05551
15.542-19.650 mmol/L. From SI to US units x18.

Creat- 0.1-0.5 mg/dl. In SI units this is measured as umol/L. Conversion x 88.4
8.84-44.2 umol/L.  To convert SI units to US units x.0113

Phos- 3.5-6.9 mg/dl. SI units measures using mmol/L with conversion x.3229
1.13-2.228 mmol/L. To convert SI units to US units x 3.097

While this is not all the conversions, these will be a help and show how different the systems of measure are. Nothing worried me more, then hearing on different mailing lists what the Calcium level of my birds should be and knowing my vet had told me a totally different number. I hope this small sampling of conversions will spare someone else that worry.