1. A plastic container comprising:
a tubular sidewall;
a base merging with the sidewall, the base including an annular bearing surface comprising a weak point, and an inner portion for accommodating inner forces tending to collapse the sidewall, the inner portion having a hinge for facilitating the inward collapse of the inner portion, a vacuum panel, and a support ring interposed between the hinge and the vacuum panel to maintain the shape of the vacuum panel as the inner portion collapses.
2. The plastic container according to claim 1, wherein the vacuum panel extends outward.
3. The plastic container according to claim 1, wherein at least one of the vacuum panel or the inner portion flexes inward when a vacuum is created inside the plastic container.
4. The plastic container according to claim 1, wherein the annular bearing surface curls inward at the weak point to further facilitate the inward collapse of the inner portion.
5. The plastic container according to claim 3, wherein the inner portion flexes by an amount sufficient to prevent deformation of the annular bearing surface when a vacuum is created inside the container.
6. The plastic container according to claim 4, wherein the inner portion flexes without deforming at least one of the sidewall and the base.
7. The plastic container according to claim 1, wherein the sidewall is substantially cylindrical.
8. The plastic container according to claim 1, wherein the sidewall is substantially smooth.
9. The plastic container according to claim 1, wherein the plastic container is composed of polyolefin.
10. The plastic container according to claim 9, wherein the polyolefin is polyethylene or polypropylene.
11. A plastic container comprising:
a substantially cylindrical sidewall;
a base merging with the sidewall, the base including an annular bearing surface comprising a weak point, and an inner portion having an annular hinge, a support ring, and a vacuum panel surrounded by the annular hinge and the support ring,
wherein the inner portion extends outward under a first state and flexes inward when a vacuum is created inside the plastic container.
12. The plastic container according to claim 11, wherein the inner portion flexes without deforming at least one of the sidewall and the base.
13. The plastic container according to claim 11, wherein the sidewall is substantially smooth.
14. The plastic container according to claim 11, wherein the plastic container comprises a plastic.
15. The plastic container according to claim 14, wherein the plastic is a polyolefin.
16. The plastic container according to claim 15, wherein the polyolefin is selected from polyethylene and polypropylene.
17. The plastic container according to claim 11, wherein the annular bearing surface curls inward at the weak point to further facilitate the inward collapse of the inner portion.
18. A plastic container comprising:
a substantially smooth, cylindrical sidewall;
a base merging with the sidewall, the base including an annular bearing surface comprising a weak point, and an inner portion having an annular hinge, a support ring, and a vacuum panel surrounded by the annular hinge and the support ring,
wherein the inner portion extends outward under a first state and flexes inward when a vacuum is created inside the plastic container without deforming the at least one of the sidewall and the base.
19. The plastic container according to claim 18, wherein the plastic container is composed of polyolefin.
20. The plastic container according to claim 19, wherein the plastic container is composed of polyethylene.
21. The plastic container according to claim 19, wherein the plastic container is composed of polypropylene.
22. The plastic container according to claim 18, wherein the annular bearing surface curls inward at the weak point to further facilitate the inward collapse of the inner portion.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A method of assaying a sample of blood or blood components for the presence of 25-hydroxy-vitamin D comprising:
(a) lowering the pH of the sample to 5.5 or less to dissociate the 25-hydroxy-vitamin D from vitamin D binding proteins; and
(b) determining the concentration of 25-hydroxy-vitamin D in the sample,
wherein the vitamin D binding proteins are not removed from the sample.
2. The method of claim 1, wherein the pH of the sample is lowered to 5 or less.
3. The method of claim 1, wherein the pH of the sample is lowered to 4.5 or less.
4. The method of claim 1, wherein the pH of the sample is lowered to 4 or less.
5. The method of claim 1, wherein the pH of the sample is lowered to 3 or less.
6. The method of claim 1, wherein the pH of the sample is lowered to be in the range of from 2 to 5.5.
7. The method of claim 1, wherein the pH of the sample is lowered to be in the range of from 4.0 to 4.5.
8. The method of claim 1, wherein the pH of the sample is lowered to 5.5 or less by adding a buffer having a pH of less than 5.5.
9. The method of claim 8, wherein the buffer is a citrate, citrate phosphate, or acetate buffer.
10. The method of claim 1, wherein the concentration of 25-hydroxy-vitamin D is determined by immunoassay.
11. The method of claim 1, wherein the sample of blood or blood components is serum or plasma.
12. The method of claim 1, wherein no precipitate is formed.
13. A method of claim 10, wherein a vitamin D tracer is used in the immunoassay.
14. A method of claim 13, wherein the vitamin D tracer is ABEI conjugated to 25-hydroxy-vitamin D.
15. A method of claim 13, wherein the vitamin D tracer is ABEI conjugated to a 22-carboxylic acid derivative of 25-hydroxy-vitamin D by a 2,2-(Ethylenedioxy)diethylamine linker.
16. A method of claim 13, wherein the vitamin D tracer is ABEI conjugated to a 22-carboxylic acid derivative of 25-hydroxy-vitamin D by a polyethylene glycol linker.
17. A method of claim 13, wherein the vitamin D tracer is ABEI conjugated to a 22-carboxylic acid derivative of 25-hydroxy-vitamin D by a dimethyl adipimidate linker.
18. A method of claim 13, wherein the vitamin D tracer is ABEI conjugated to a 22-carboxylic acid derivative of 25-hydroxy-vitamin D by a diamino cyclohexane linker.
19. A method of claim 13, wherein the vitamin D tracer is ABEI conjugated to a 22-carboxylic acid derivative of 25-hydroxy-vitamin D by a diamino C3- to C12-chain linker.