Fig 1.
Comparison of Syringe Combinations Tested in This Study.
(A) From left to right, the photo shows an insulin syringe with attached needle, a 1 ml tuberculin syringe with detachable needle, a 3 ml Luer-lock syringe with detachable needle, a 2.5 Noloss syringe with the piston withdrawn from the hub of the syringe. (B) Going clockwise from the upper left, the photo shows a 23 gauge, 1¼” standard needle, a 25 gauge, 5/8” standard needle, a 25 gauge, 5/8” lower dead space (LDS) needle, and a 23 gauge, 1¼” standard lower dead space (LDS) needle. Note the addition plastic inside the LDS needles that serve to reduce the dead space. Photographs courtesy of Michael Greenwood.
Fig 2.
Flow diagram of syringe testing.
Syringe-needle pairs were contaminated with virus and tested for viable HCV immediately after contamination, after storage at room temperature or after rinsing with water.
Fig 3.
Residual liquid and residual viable HCV in LDS and HDS syringe-needle combinations.
(A) Syringe-needle pairs were rinsed with brilliant yellow dye solution and residual volumes were determined with absorbance measurements at 260nm. Syringe-needle pairs were also loaded with plasma spiked with HCV and (B) the frequency of HCV-positive syringes was determined. Each data point denotes the average residual volumes ±SD from 3 syringes or the percentage of HCV-positive syringes ±95% C.I. from at least 3 experiments. G = gauge. LDS = low dead space.
Table 1.
Comparison of HCV Recovery and Residual Infectivity Immediately after Contamination.
Fig 4.
HCV stability in LDS and HDS syringe-needle combinations stored at room temperature.
Syringe-needle pairs were loaded with plasma spiked with HCV and stored at room temperature for up to 1 week. The frequency of HCV-positive syringes with (A) 27-gauge, (B) 25-gauage, and (C) 23-gauge needle size was determined. Data from insulin syringes with fixed 27-gauge needles are repeated on each graph for comparison purposes (open circles and dashed lines). The percent HCV-positive syringes ±95% C.I. from at least 3 experiments are represented by each data point. G = gauge. LDS = low dead space.
Table 2.
Half-life and 95% Confidence Intervals for HCV Recovery Following Storage of HCV Contaminated Syringe/Needle Combinations.
Fig 5.
Effect of needle size on HCV retention in the syringes-needle combinations.
Syringe-needle pairs were loaded with HCV-spiked plasma and stored at room temperature for up to 1 week. The percentage of HCV-positive (A) 2 mL Noloss LDS and (B) 1 mL tuberculin syringes was determined. Each data point denotes the percentage of HCV-positive syringes ±95% C.I. from at least 3 experiments. G = gauge. LDS = low dead space.
Fig 6.
Residual viable HCV in LDS and HDS syringe-needle combinations after rinsing with water.
Syringes were loaded with plasma spiked with HCV and rinsed once or twice with water and the frequency of HCV-positive syringes was determined. The percentage of HCV-positive syringes ±95% C.I. from at least 3 experiments are represented by each data point. G = Gauge. LDS = low dead space.