Heparin (Unfractionated)¶
Overview¶
| Field | Detail |
|---|---|
| Drug class | Unfractionated Heparin (UFH) |
| Stock vial | 5000 U/mL (Common) or 25,000 U/5 mL (5000 U/mL) |
| Reconstituted conc. | N/A (Ready to use) |
| Storage | Room temp |
Preparation¶
Before you start
Check the concentration. Usually 5000 U/mL. Note that heparin can cause delayed-type hypersensitivity (DTH) reactions similar to LMWH.
Equipment needed¶
- 1 × Heparin 5000 U/mL vial
- Normal saline (NS) — for IDT dilutions
- 1 mL syringes × 3 (for test doses/dilutions)
- 25 G needles
Step 1 — Prepare the SPT solution (5000 U/mL — neat)¶
- Draw up 0.5–1 mL of the stock (5000 U/mL) into a 1 mL syringe.
- Label: "Heparin SPT 5000 U/mL".
Step 2 — Prepare IDT dilutions¶
Prepare in this order, using a fresh syringe for each step.
- IDT 5 U/mL (1:1,000):
- Draw 0.1 mL of stock (5000 U/mL) into a 1 mL syringe. Add 0.9 mL NS. Mix. (This is 500 U/mL — 1:10).
- Draw 0.1 mL of this 500 U/mL into a new 1 mL syringe. Add 0.9 mL NS. Mix. (This is 50 U/mL — 1:100).
- Draw 0.1 mL of this 50 U/mL into a new 1 mL syringe. Add 0.9 mL NS. Mix. (This is 5 U/mL — 1:1,000).
- Label: "Heparin IDT 5 U/mL".
Skin prick test (SPT)¶
| Reagent | Concentration |
|---|---|
| Test solution | Neat (5000 U/mL) |
| Positive control | Histamine 10 mg/mL |
| Negative control | Normal saline |
Interpretation: Wheal ≥3 mm vs negative control = positive.
Intradermal test (IDT)¶
Dilution series¶
| Step | Dilution | Concentration | Preparation |
|---|---|---|---|
| 1 | 1:1,000 | 5 U/mL | 0.1 mL of 50 U/mL + 0.9 mL NS |
Inject: 0.05 mL intradermal. Read at 15–20 minutes. Delayed Reading: If history is suggestive of a delayed reaction (DTH), re-read at 24 and 48 hours.