U100-concentrated insulin has 100 units per ml of liquid, and should be used with U100 syringes.

Cubic centimeters (cc's) and milliliters (mL's) are interchangable, so syringes marked 1ml equals 1cc; 0.5 ml equals 1/2cc. 3/10cc equals 0.3ml. ^[1]

Because U100 insulin syringes are designed for human use, they are available from brick-and-mortar or Internet pharmacies that sell diabetic supplies. You also can order from an Internet pet pharmacy such as Drs. Foster & Smith. ^[2]

In the US, you can expect to pay $15 to $25 for a box of 100 U100 syringes depending on the retailer and the features of the syringe. Some states and countries ^[3] require a prescription.

General information and an overview of syringes at the link.

Contents 1 Barrel 2 Visual guide to barrel markings 3 Needle 4 Gauge 5 Conversion 6 References 7 More Information

BarrelEdit

U100 syringes are available in 3 barrel sizes: 1cc (1 ml), 1/2cc (0.5 ml), and 3/10cc (0.3 ml). The size refers to the maximum volume of insulin the syringe will hold; markings can differ with regard to the size of the syringe and the syringe manufacturer. ^[4] Note that ReliOn states all of its 3/10 cc (0.3ml) insulin syringes have half scale/half unit markings. ^[5]

U-100 Syringe Sizes
1cc (1 ml) Syringe
Holds maximum:	100 units [6]
Numbered in:	10 unit increments [7]
Smallest line measures 2 units: [8]	BD [9] ReliOn [10] Monoject [11] (all but 31 gauge needle)
Smallest line measures 1 unit:	Easy Touch [12] Precision Sure Dose[13] UltiCare [14] Monoject [15] (31 gauge needle only)
1/2cc (0.5 ml) Syringe
Holds maximum:	50 units [16]
Numbered in:	10 unit increments [17]
Smallest line measures 1 unit: [18]	BD [19] Precision Sure Dose[20] Ulti-Care [21][22] Easy Touch [23] ReliOn[24] Monoject [25]
3/10cc (0.3 ml) Syringe
Holds maximum:	30 units [26]
Numbered in:	5 unit increments [27]
Smallest line measures 1 unit: [28]	BD Micro Fine [29] BD Ultra Fine [30][31] (standard length only) Monoject [32] Easy Touch [33] UltiCare [34]
Half-unit scale 3/10cc (0.3 ml) Syringe  [35]
Holds maximum:	30 units [36]
Numbered in:	5 unit increments [37]
Smallest line measures 1/2 unit:	BD Ultra Fine II (short) [38][39] ReliOn [40][41]

If for any reason you need to change the size of the syringe you normally use, extra care at drawing insulin will be needed. Those normally using 3/10 cc syringes, with single or half unit markings, could risk giving too much insulin by following the mark on 1cc syringes. Some brands of 1cc syringes have their smallest non-numbered marks at 2 units, ^[42] others have theirs at 1 unit.^[43]

The 3/10cc syringe has 1 unit marks. Some manufacturers also have 3/10cc syringes with 1/2 unit marks referred to as half-unit scale or half-scale markings, as seen on the table above ^[44] and in the photo below.

Visual guide to barrel markingsEdit

NeedleEdit

U100 syringes come with a standard long (12.7mm or 1/2”) or short (8mm or 5/16”) needle. Most syringes with 1/2 unit markings come in the short length, although some manufacturers do put long needles on barrels with 1/2 unit markings.

Some caregivers prefer the long needle so that they make sure they make it through the fur to the skin. Some feline caregivers prefer the short needle because it minimizes the chance that they will “shoot through” the tent and spill the insulin onto the pet’s fur on the other side. However, some caregivers report difference in insulin absorption with different length needles. BD Diabetes ^[45] explains that you should consult with your health care professional before using a short needle, and carefully monitor blood glucose when changing to a shorter needle. Some people have found their blood glucose not well-controlled when switching to the shorter needles; this also has been the case with some dogs. Switching back to a longer needle solved the problem. You should consider experimenting with the different length needles. AAHA recommends using standard (12.7mm or 1/2”) length needles. ^[46]

GaugeEdit

U100 syringes come in different thicknesses of needle: the gauge (rhymes with "cage"). The higher the gauge number, the thinner the needle. ^[47] Common gauges range from 28 to 31. Caregivers report that thinner needles make the shot more comfortable for the pet. The 31 gauge syringes are available only with short needles. A 2000 study of children with diabetes ranging in age from 8-21 years compared bleeding, pain/discomfort and insulin leakage using 27-30 gauge needles. Overall, the doctors found no significant differences between any of the needle gauges used. ^[48] AAHA recommends using 29 gauge needles. ^[49]

ConversionEdit

Though it's not recommended by veterinarians, some caregivers use a U100 syringe with a U40 insulin. That requires “converting” the U40 concentration to a U100 strength. ^[50] See the conversion table. If you choose to use the U100 syringes for U40 insulin, a fast way to calculate the right amount of units is to multiply the number of U40 units given by 2.5.

The advantage of doing this conversion is the possibility of greater precision for low-dose animals -- precise dose increments of 0.2 units are possible with half-unit marked U100 syringes (if your insulin is U40). On the other hand, if you find the conversion confusing, it's best not to try -- it can be extremely dangerous to get this math wrong.

Conversion Chart for Using U-40 Insulin With U-100 Syringes [51]
To get this many units of U-40 insulin	Fill a U-100 syringe to this mark
0.25	0.6
0.50	1.3
0.75	1.9
1.00	2.5
1.25	3.1
1.50	3.8
1.75	4.4
2.00	5.0
2.25	5.6
2.50	6.3
2.75	6.9
3.00	7.5
3.25	8.1
3.50	8.8
3.75	9.4
4.00	10.0
4.25	10.6
4.50	11.3
4.75	11.9
5.00	12.5
5.25	13.1
5.50	13.8
5.75	14.4
6.00	15.0
6.25	15.6
6.50	16.3
6.75	16.9
7.00	17.5
7.25	18.1
7.50	18.8
7.75	19.4
8.00	20.0
8.25	20.6
8.50	21.3
8.75	21.9
9.00	22.5
9.25	23.1
9.50	23.8
9.75	24.4
10.00	25.0
10.25	25.6
10.50	26.3
10.75	26.9
11.00	27.5
11.25	28.1
11.50	28.8
11.75	29.4
12.0	30.0

ReferencesEdit

1. ↑ Milliliter to Cubic Centimeter Converter. Calculateme.com.
2. ↑ Drs. Foster & Smith Website.
3. ↑ Syringes--Prescription Needed or Not?. Childrenwithdiabetes.com.
4. ↑ Insulin Therapy-Insulin Syringes. RxEd.org.
5. ↑ ReliOn-all 3/10 Syringes with half-unit markings.
6. ↑ Close-up of BD 1cc Syringes-UltraFine-30 Gauge-1/2", UltraFine II Short-31 Gauge-5/16" & MicroFine-28 Gauge-1/2".
7. ↑ Close-up of BD 1cc Syringes-UltraFine-30 Gauge-1/2", UltraFine II Short-31 Gauge-5/16" & MicroFine-28 Gauge-1/2".
8. ↑ Diabetes Mellitus. Washington State University.
9. ↑ Close-up of BD 1cc Syringes-UltraFine-30 Gauge-1/2", UltraFine II Short-31 Gauge-5/16" & MicroFine-28 Gauge-1/2".
10. ↑ ReliOn Insulin Syringe Markings.
11. ↑ Diabetes Health Syringe Listings.
12. ↑ Easy Touch Syringe demonstration-their syringes all measure in 1 unit increments.
13. ↑ Diabetes Health Syringe Listings.
14. ↑ Diabetes Health Syringe Listings.
15. ↑ Diabetes Health Syringe Listings.
16. ↑ Close-up of BD 1/2 cc Syringes--UltraFine-30 Gauge-1/2", UltraFine II Short-31 Gauge-5/16" & MicroFine-28 Gauge-1/2".
17. ↑ Close-up of BD 1/2 cc Syringes--UltraFine-30 Gauge-1/2", UltraFine II Short-31 Gauge-5/16" & MicroFine-28 Gauge-1/2".
18. ↑ Diabetes Mellitus. Washington State University.
19. ↑ Close-up of BD 1/2 cc Syringes--UltraFine-30 Gauge-1/2", UltraFine II Short-31 Gauge-5/16" & MicroFine-28 Gauge-1/2".
20. ↑ Diabetes Health Syringe Listings.
21. ↑ Ulti-Care U100 Syringes-Product Information.
22. ↑ Diabetes Health Syringe Listings.
23. ↑ Easy Touch Syringes demonstration-all syringes with 1 unit increment markings.
24. ↑ ReliOn Insulin Syringe Markings.
25. ↑ Diabetes Health Syringe Listings.
26. ↑ Close-up of BD 3/10 Syringes-UltraFine-30 Gauge-1/2", UltraFine II Short-31 Gauge-5/16", UltraFine Short-Half Unit Markings-31 Gauge-5/16" & MicroFine-28 Gauge-1/2".
27. ↑ Close-up of BD 3/10 Syringes-UltraFine-30 Gauge-1/2", UltraFine II Short-31 Gauge-5/16", UltraFine Short-Half Unit Markings-31 Gauge-5/16" & MicroFine-28 Gauge-1/2".
28. ↑ Diabetes Mellitus. -Washington State University.
29. ↑ Diabetes Health Syringe Listings.
30. ↑ Close-up of BD 3/10 Syringes-UltraFine-30 Gauge-1/2", UltraFine II Short-31 Gauge-5/16", UltraFine Short-Half Unit Markings-31 Gauge-5/16" & MicroFine-28 Gauge-1/2".
31. ↑ Diabetes Health Syringe Listings.
32. ↑ Diabetes Health Syringe Listings.
33. ↑ Easy Touch Syringes-all products measure in 1 unit increment markings.
34. ↑ Diabetes Health Syringe Listings.
35. ↑ Comparison of 3/10 cc syringe marks--half unit and whole unit scale. BD.
36. ↑ Close-up of BD 3/10 Syringes-UltraFine-30 Gauge-1/2", UltraFine II Short-31 Gauge-5/16", UltraFine Short-Half Unit Markings-31 Gauge-5/16" & MicroFine-28 Gauge-1/2".
37. ↑ Close-up of BD 3/10 Syringes-UltraFine-30 Gauge-1/2", UltraFine II Short-31 Gauge-5/16", UltraFine Short-Half Unit Markings-31 Gauge-5/16" & MicroFine-28 Gauge-1/2".
38. ↑ Close-up of BD 3/10 Syringes-UltraFine-30 Gauge-1/2", UltraFine II Short-31 Gauge-5/16", UltraFine Short-Half Unit Markings-31 Gauge-5/16" & MicroFine-28 Gauge-1/2".
39. ↑ Diabetes Health Syringe Listings.
40. ↑ ReliOn Insulin Syringe Markings.
41. ↑ Diabetes Health Syringe Listings.
42. ↑ Diabetes Health Syringe Listings.
43. ↑ Ulti-Care U100 Syringes-Product Information.
44. ↑ Comparison of 3/10 cc syringe marks-half unit and whole unit scale. BD.
45. ↑ Using Short Needles. BDdiabetes.com.
46. ↑ Ruchinsky, Renee, et. al. (2010). Diabetes Management Guidelines for Dogs and Cats-page 9. American Animal Hospital Association.
47. ↑ BD Diabetes Insulin Syringe Needles.
48. ↑ Hanas, Ragnar, et. al. (2000). Thinner Needles Do Not Influence Injection Pain, Insulin Leakage or Bleeding in Children & Adolescents With Type 1 Diabetes. Pediatric Diabetes.
49. ↑ Ruchinsky, Renee, et. al. (2010). Diabetes Management Guidelines for Dogs and Cats-page 9. American Animal Hospital Association.
50. ↑ Using Caninsulin With U100 Syringes-Page 2. Intervet.
51. ↑ U 40 Insulin/U 100 Syringe Conversion Chart. MediVet.

More InformationEdit

• Diabetes Mellitus Washington State University
  Good general information--photos and tips about how to draw insulin.
• Needle Re-Use BD Diabetes
• Childrenwithdiabetes.com-U40 & U100 Insulin
• ReliOn Insulin Syringe Needle Lengths-U 100 insulin
• ReliOn Insulin Syringes-U 100 insulin-FAQ's
• More Tips on Drawing Insulin From a Disposable Pen
• Diabetes Health listing of all U100 syringes sold in the US, marking information, needle length/gauge, etc.