DRAFT UGANDA STANDARD  
  DUS 1958 -1 
First Edition  
2018 -mm-dd 
 
 
 DUS 1958 -1: 2018 
© UNBS 2018   
  
Surgical sutures — Specification — Part 1: Absorbable  
 DUS 1958 -1: 2018  
ii © UNBS 2018  – All rights reserved  
 Compliance with this standard does not, of itself confer immunity from legal obligations  
A Uganda Standard does not purport to include all necessary provisions of a contract. Users are 
responsible fo r its correct application  
© UNBS 2018   
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The Executive Director  
Uganda National Bureau of Standards  
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Kampala  
Uganda  
Tel: +256 41 4 333 2 50/1/2/3  
Fax: +256 41 4 286 123  
E-mail: info@unbs.go.ug  
Web: www.unbs.go.ug  DUS 1958 -1:2018  
© UNBS 2018  – All rights reserved  iii 
 Foreword  
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry of Trade , Industry and 
Cooperatives established under Cap 327 , of the Laws of Uganda , as amended .  UNBS  is mandated to co -
ordinate the elaboration of standards and is  
(a) a member of International Organisation for Standardisation (ISO) and  
(b) a contact point for the WHO/FAO Codex Alimentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT  Agreement  of the World Trade Organisation (WTO).  
The work of preparing Uganda Standards is carried out through Technical Committees. A Technical 
Committee is established to deliberate on standards in a given field or area and consists of key stakeholders 
including government, academia, consumer groups, private sector and other interested parties.  
Draft Uganda Standards adopted by the Technical Committee are widely circulated to stakeholders and the 
general public for comments. The committee reviews the comm ents before recommending the draft standards 
for approval and declaration as Uganda Standards by the National Standards Council.  
The committee responsible for this document is Technical Committee UNBS /TC 14, Medical devices.  
DUS 1958 consists of the follo wing parts, under the Surgical  sutures — Specification  
  Part 1: Surgical sutur es — Specification — Part 1: A bsorbable   
  Part 2: Surgical sutures — Specification — Part 2:  Non Absorbable  DUS 1958 -1: 2018  
iv © UNBS 2018  – All rights reserved  
 Introduction  
Surgical s utures are used in a variety of different s urgical procedures to close wounds and aid in tissue 
healing.  These sutures may be a single filament or multifilament or braided or twisted with or without a coating  
Surgical sutures are classified into two types:  
a) Absorbable surgical sutures  
b) Non-absorbable  surgical sutures  
 DRAFT UGANDA STANDARD  DUS 1958 -1: 2018  
 
© UNBS  2018  – All rights reserved  1 
 Surgical sutures  — Specification  — Part 1: Absorbable  
1 Scope   
This Draft Uganda Standard specifie s the requirements , sampling and test methods for absorbable surgical 
sutures  
2 Normative references   
The following referenced documents r eferred to in the text in such a way that some or all of their content 
constitutes requirements of this document. For dated references, only the edition cited applies. For undated 
references, the latest edition of the referenced document (including any ame ndments) applies.  
US ISO 24153 —.Random sampling and randomisation procedures.  
3 Terms and definitions   
For the purposes of this document, the following terms and definitions apply.  
ISO and IEC maintain terminological databases for use in standardization at the following addresses:  
— ISO Online browsing platform: available at http://www.iso.org/obp  
3.1 
absorbable sutures  
sutures capable of being absorbed by living animal tissues.  
3.2  
monofilament  
suture  made of a single strand  
3.3  
multifilament  
suture c omposed of several filaments twisted or braided together  
3.4 
surgical sutures  
medical devices that are used to hold body tissues together after a surgery or injury . 
4 Types  of absorbable sutures  
4.1 Natural absorbable sutures  
Sutures prepared from collagen  derived from healthy mammals.  Natural absorbable sutures are categorized 
into two: plain and chromic gut.  DUS 1958 -1:2018  
2 © UNBS 2018  – All rights reserved  
 4.2 Synthetic absorbable sutures  
Sutures prepared from a synthetic  polymer, polymers or copolymers which, when introduced into a living 
organism , are  absorbed by that organism and cause no undue tissue irritation.  They consist of completely 
polymerized material.  
5 General description  
5.1 The suture shall either be monofilament or multifilament. If multifilament, the individual filament may be 
combined by spinning, twisting, braiding or any combination.  
5.2 It may be coloured,  coated  or bot h. 
6 Quality requirements  
6.1 Length  
The length  of the suture without stretching shall be  not less than 95 per cent of the length stated on  the label  
and shall not  exceed 400 cm . 
6.2 Diameter  
6.2.1  Collagen suture  — When determined in accordance with  Annex A, the average diameter, and not 
fewer than 20, of the 30 measurements on the 10 -strand sample are within the limits on average diameter 
prescribed in Table  1. None o f the individual measurements is less than the midpoint of the range for the next 
smaller size or more than the midpoint of the range for the next larger size.  
6.2.2  Synthetic suture  — When determined in accordance with Annex A,  the average diameter of the  
strands being measured is within the tolerances prescribed in  Table 2 . None of the observed measurements is 
less than the midpoint of the range for the next smaller size or more than the midpoint of the range for the next 
larger size.  DUS 1958 -1: 2018  
© UNBS 2018  – All rights reserved  3 
 Table 1 — Diameter and tensile strength of natural (collagen) sutures  
Gauge 
number 
(Metric size)  Limits on average diameter (mm)  Knot pull tensile strength (kgf)  Knot pull tensile 
strength( N)  
Min  max Limit on 
average min.  Limit on individual 
strand ,min  Limit on 
average min.  Limit on 
individual 
strand 
,min 
0.4 0.040  0.049  - - - - 
0.5 0.050  0.069  0.045  0.025  0.44 0.24 
0.7 0.070  0.099  0.07 0.055  0.69 0.54 
1 0.10 0.149  0.18 0.10 1.76 0.98 
1.5 0.15 0.199  0.38 0.20 3.73 1.96 
2 0.20 0.249  0.77 0.40 7.55 3.92 
3 0.30 0.339  1.25 0.68 12.2 6.67 
3.5 0.35 0.399  2.00 1.04 19.6 10.2 
4 0.40 0.499  2.77 1.45 27.2 14.2 
5 0.50 0.599  3.80 1.95 37.3 19.1 
6 0.60 0.699  4.51 2.40 44.2 25.5 
7 0.70 0.799  5.90 2.99 57.8 29.3 
8 0.80 0.899  7.00 3.49 68.6 34.2 
Table 2 — Diameter and tensile strength of Synthetic Suture s 
Gauge 
number 
(Metric Size)  Limits on Average Diameter 
(mm)  Knot -Pull Tensile (in kgf) 
(except where Strength 
other wise specified)* Limit on 
Average Min.  Knot -Pull Tensile Strength 
(in N) (except where 
otherwise specified)  Min  Max  
0.01 0.001  0.009  — — 
0.1 0.010  0.019  — — 
0.2 0.020  0.029 *  0.025  0.24*  
0.3 0.030  0.039  0.050*  0.49*  
0.4 0.040  0.049  0.07 0.69 
0.5 0.050  0.069  0.14 1.37 
0.7 0.070  0.099  0.25 2.45 
1 0.10 0.149  0.68 6.67 
1.5 0.15 0.199  0.95 9.32 
2 0.20 0.249  1.77 17.4 
3 0.30 0.339  2.68 26.3 
3.5 0.35 0.399  3.90 38.2 
4 0.40 0.499  5.08 49.8 
5 0.50 0.599  6.35 62.3 
6 0.60 0.699  7.29 71.5 
7 0.70 0.799 — — 
 DUS 1958 -1:2018  
4 © UNBS 2018  – All rights reserved  
 6.3 Minimum breaking load (tensile strength)  
6.3.1  Collagen suture  
When determine on not fewer t han 10 strands of Suture as prescribed in Annex B, the tensile strength, 
determined as the minimum strength for each individual strand tested, and ca lculated as the average strength 
from any one lot, is as set forth in  Table 1 . If not more than one strand fails to meet the limit on individual 
strands, repeat the test with not fewer than 20 additional strands: the requirements of the test are met if none 
of the additional strands falls below the limit on individual strands, and if the average strength of all the strands 
tested does not fall below th e stated limit in  Table 1 . 
6.3.2 Synthetic suture  
When determine on not fewer than 10 strands of Suture as per Annex B,  The minimum tensile strength of 
each size of synthetic suture, calculated as the average strength from any one lot, is as set forth in  Table 2 . 
6.4 Needle attachment  
6.4.1  If the sutures are supplied with an eyeless needle attached that is not stated to be detachable, they 
shall comply with the  requirements given in table 3 when  tested for needle attachment  as prescribed in annex 
C. 
6.4.2  If sutures are supplied with removable ne edle, they shall comply with the requirements given in table 
4 when tested in accordance with annex C.  
Table 3 — Needle Attachment for Absorbable suture s 
Gauge Number  Limits on Needle Attachment  
Natural(collagen) 
Absorbable 
Suture  Synthetic 
Absorbable 
Sutures Average (in  
kgf) (Min.)  Individual (in  
kgf) (Min.)  Average (in N)  
(Min.)  Individual (in N)  
(Min.)  
- 0.1 0.007  0.005  0.069  0.049  
- 0.2 0.014  0.010  0.137  0.098  
0.4 0.3 0.021  0.015  0.206  0.147  
0.5 0.4  0.050  0.025  0.490  0.245  
0.7  0.5 0.080  0.040  0.784 0.392  
1 0.7 0.17 0.08 1.67 0.784  
1.5 1 0.23  0.11 2.25 1.08 
2  1.5 0.45 0.23 4.41 2.25 
3  2 0.68  0.34 6.67 3.33 
3.5 3 1.10  0.45 10.8 4.41 
4 3.5 1.50 0.45 14.7 4.41 
5 4 1.80  0.60 17.6 5.88 
6 and larger  5 and larger  1.80 0.70 17.6 6.86 
 DUS 1958 -1: 2018  
© UNBS 2018  – All rights reserved  5 
 Table 4 — Removable Needle Attachment for Absorbable sutures  
Gauge Number  Limits on Needle Attachment  
Natural(collagen) 
Absorbable 
Suture  Synthetic 
Absorbable 
Sutures  minimum (in kgf)  Maximum (in kgf)  Minimum (in N)  Maximum (in N)  
1.5  1 0.028  1.59 0.274  15.6 
2  1.5 0.028  1.59 0.274  15.6 
3 2 0.028  1.59 0.274  15.6 
3.5 3 0.028  1.59 0.274  15.6 
4 3.5 0.028  1.59 0.274  15.6 
5 4 0.028  1.59 0.274  15.6 
6 5 0.028  1.59 0.274  15.6 
 
6.5 Extractable colour  
Dyed sutures shall be  colour fast when tested  in accord ance with Anne x D.  
6.6 sterility  
It shall be sterile when tested in accordance with annex E 
7 Pack aging 
7.1 The sterile sutures (dry or in fluid) shall be packed in sachets or packets or containers that maintain 
sterility until the container is opened and  allows the withdrawal and use of the suture in aseptic conditions.  
7.2 A number of sachets (packets or containers) may be packaged in a box . 
8 Labelling  
8.1 The primary package of the suture shall be legibly  and indelibly  marked with the following inform ation:  
a) Name and address of manufacturer;  
b) name of the product,  
c) size of the suture; (gauge number)  
d) material and composition,  
e) type of suture( absorbable) ; 
f) structure (monofilament , or multifilament ); 
g) length of suture, in centimetres;  
h) if appropriate, tha t the suture is coloured,  
i) batch number;  DUS 1958 -1:2018  
6 © UNBS 2018  – All rights reserved  
 j) absorption time,  
k) sterile ; 
l) kind of needle if included;  
m) Warnings, like “DO NOT RESTERILIZE. DISCARD OPEN UNUSED SUTURES. STORE AT ROOM 
TEMPERATURE. AVOID PROLONGED EXPOSURE TO ELEVATED TEMPERATURES” ; and 
n) date of manufa cture and expiry.  
8.2 If the sachets (packets or containers) are packaged in boxes, the boxes shall be labelle d with the 
following  
i) name and address of the manufacturer/ packer/distributor;  
ii) name of product;  
iii) type of suture( absorbable);  
iv) structure (monofilam ent or multifilament ); 
v) composition of any packaging fluid if used;  
vi) batch number;  
vii) name of product;  and  
viii) sterile  
Note — if the suture is packaged with a fluid, make sure that testing is done within 2 minutes after 
removing it from the fluid.  
9 Sampling  
Sampling shall be don e in accordance with US ISO 24153  DUS 1958 -1: 2018  
© UNBS 2018  – All rights reserved  7 
 Annex  A 
(normative)  
 
Diameter of sutures  
A.1 Introduction  
The gauge for determining the diameter of the suture is of the dead -weight type, mechanical or electrical, and 
equipped with a direct -reading dial, a digital reado ut, or a printed readout. Use a gauge graduated to 0.002 
mm or smaller. The anvil of the gauge is about 50 mm in diameter, and the presser foot is 12.70 ± 0.02 mm in 
diameter. The presser foot and moving parts connected therewith are weighted so as to appl y a total load of 
210 ± 3 g to the specimen. The presser foot and anvil surfaces are plane to within 0.005 mm and parallel to 
each other to within 0.005 mm . For measuring the diameter of metric size 0.4 and smaller, remove the 
additional weight from the pr esser foot so that the total load on the suture does not exceed 60 g.  
A.2 Natural (Collagen) absorbable sutures.  
A.2.1 Carry out the test on 10 sutures . Determine the diameter immediately after removal from the 
container or packet and without stretching.  
A.2.2 Lay the strand across the centre of the anvil and the pressor foot, and gently lower the foot until its 
entire weight rests upon the suture  
A.2.3 Lower the pressor foot slowly to avoid crushing the suture. Measure the diameter at at three points 
along the suture strand at intervals of 30 cm over the whole length of the suture.  
A.2.5 For a suture less than 90 cm in length, measure at 3 points approximately evenly spaced along the 
suture.  The suture is not subjected to more tension than is necessary to  keep it straight during measurement.  
A.3 Synthetic absorbable sutures  
A.3.1 Lay the strand across the center of the anvil and presser foot, and gently lower the foot until its entire 
weight rests upon the suture.  
A.3.2 Measure the diameter of the suture at three points corresponding roughly to one -fourth, one -half, and 
three -fourths of its length. In the case of braided suture of sizes larger than 3 -0 (metric size 2), make two 
measurements at each point at right angles to each other, and use the average a s the observed diameter at 
that point.  
A.3.3 In measuring multifilament , attach a portion of the designated section of the strand in a fixed clamp in 
such a way that the strand lies across the center of the anvil. While holding the strand in the same plane  as 
the surface of the anvil, place the strand under tension by suitable means, taking care not to permit the strand, 
if twisted, to untwist. Measure the diameter at the designated points on the strand, and calculate the average 
diameter . DUS 1958 -1:2018  
8 © UNBS 2018  – All rights reserved  
 Annex  B 
(normativ e) 
 
Minimum breaking load  
B.1 Introduction  
Carry out test on five sutures. The  minimum breaking load is determined over a sim ple knot formed by placing 
one end of a suture held in the right hand over the ot her end held in the left hand, passing one end over the 
suture and through the loop so formed (see Figure B1) and pulling the knot tight.  
 
Figure B1 — Simple knot  
B.2 Collagen absorbable sutures  
Refer to Table 1  for breaking load.  
B.3 Synthetic absorbabl e sutures  
Refer to Table 2 for breaking load . 
B.4 Procedure  
B.4.1 Determine the tensile strength of surgical suture on a motor -driven tensile strength testing machine 
having suitable clamps for holding the specimen firmly and using either the principle of constant rate of load 
on specimen or the principle of constant rate of elongation of specimen, as described below.  
B.4.2 Gauge length is defined as the interior distance between the two clamps. For gauge lengths of 125 to 
200 mm, the mobile clamp is drive n at a constant rate of elongation of 30 ± 5 cm per minute. For gauge 
lengths of less than 125 mm, the rate of elongation per minute is adjusted to equal 2 times the gauge length 
per minute. For example, a 5 -cm gauge length has a rate of elongation of 10 c m per minute.  
B.4.3 Determine the tensile strength of the suture, whether packaged in dry form or in fluid, promptly after 
removal from the container, without prior drying or conditioning.  
B.4.4 Attach one end of the suture to the clamp at the load end of  the machine, pass the other end through 
the opposite clamp, applying sufficient tension so that the specimen is taut between the clamps, and engage 
the second clamp. Perform as many breaks as are specified in the individual monograph. If the break occurs 
at the clamp, discard the reading on the specimen.  DUS 1958 -1: 2018  
© UNBS 2018  – All rights reserved  9 
 Annex  C 
(normative)  
 
Needle attachment  
C.1 If the sutures are supplied with an eyeless needle attached that is not stated to be detachable, they 
shall comp ly with the requirements given  in table 3 for needle attachment  and for removable needle 
attachment, they shall comply with the table 4  
C.2 Carry out the test on 5 sutures. Use a suitable tensilometer, such as that described for the 
determination of the mi nimum breaking load.  
C.3 Fix the needle and suture (without knot) in the clamps of the apparatus in such a way that the swaged 
part of the needle is completely free of the clamp and in line with the direction of pull on the suture.  
C.4 Set the mobile cla mp in motion and note the force required to break the suture or to detach it from the 
needle.  
C.5 The average of the 5 determinations and all individual values are not less than the respective values 
given in Table 3 and table 4  
C.6 If not more than 1 ind ividual value fails to meet the individual requirement, repeat the test on an 
additional 10 sutures. The attachment complies with the test if none of these 10 values is less than the 
individual value in Table 3 and Table 4 for the gauge number concerned.  
 DUS 1958 -1:2018  
10 © UNBS 2018  – All rights reserved  
 Annex  D 
(normative)  
 
Extractable colours  
D.1 Prepare the matching solution that corresponds to the extractable colour of the suture by combing the 
colorimetric solutions in the proportions indicated in tabl e D1  and adding water, if necessary to make 10.0 
parts.  
D.2 Place 0.25 g  of suture  in a conical flask containing 1.0 ml of water for each 10 mg of the sample. Close 
the flask, and allow it to stand at 37 ± 0.5° for 24 hours.  
D.3 Cool, decant the water fro m the Suture, and compare it with the Matching Solution: any color present is 
not more intense than that of the appropriate Matching Solution  
Table D1 – Colour referencing solution.  
 DUS 1958 -1: 2018  
© UNBS 2018  – All rights reserved  11 
 Annex E 
(normative )  
 
Sterility test  
E.1 Introduction  
The following cult ure media have been found to be suitable for the test for sterility.  Fluid thioglycollate 
medium is primarily intended for the culture of anaerobic bacteria; however, it will also detect aerobic bacteria. 
Soya -bean casein digest medium is suitable for the  culture of both fungi and aerobic bacteria.  
E.2 Fluid thioglycollate medium  
L-Cystine                     0.5 g   
Agar                      0.75 g  
Sodium chloride                    2.5 g  
Glucose monohydrate/anhydrous               5.5 g/5.0 g  
Yeast extract (w ater-soluble)                 5.0 g  
Pancreatic digest of casein                  15.0 g  
Sodium thioglycollate or                  0.5 g  
Thioglycollic acid                    0.3 mL  
Resazurin sodium solution (1g/L of resazurin sodium), freshly prepared        1.0 mL  
Water R                      1000 mL  
pH after sterilisation 7.1 ± 0.2  
E.2.1 Mix the L -cystine, agar, sodium chloride, glucose, water -soluble yeast extract and pancreatic  digest of 
casein with the water R and heat until solution is effected .  
E.2.2 Dissolve the sodium thioglycollate or thioglycollic acid in the solution and, if necessary , add 1 M 
sodium hydroxide so that, after sterilisation, the solution will have  a pH of 7.1 ± 0.2. If filtration is necessary, 
heat the solution again without boiling  and filter while hot through moistened filter paper.  
E.2.3 Add the resazurin sodium  solution, mix and place the medium in suitable vessels which provide a 
ratio of  surface to depth of medium such that not more than the upper half of the medium  has undergo ne a 
colour change indicative of oxygen uptake at the end of the  incubation period. Sterilise using a validated 
process. If the medium is stored , store  at a temperature between 2 °C and 25 °C in a sterile, airtight container.  
E.2.4 If more  than the upper  one-third of the medium has acquired a pink colour, the medium  may be 
restored once by heating the containers in a water -bath or in free - flowing steam until the pink colour 
disappears and cooling quickly, taking care to prevent  the introduction of non -sterile air into the container. Do 
not use the medium for  a longer storage period than has been validated.Fluid thioglycollate medium is to be 
incubated at 30 -35 °C.  DUS 1958 -1:2018  
12 © UNBS 2018  – All rights reserved  
 E.2.5 For products containing a mercurial preservative that cannot be tested by the membran e-filtration 
method, fluid thioglycollate medium incubated at 20 -25 °C may be  used instead of soya -bean casein digest 
medium provided that it has been validated  as described in growth promotion test.  
E.3 Alternative thioglycollate medium  
Where prescribed  or justified and authorised, the following alternative thioglycollate medium  may be used. 
Prepare a mixture having the same composition as that of the  fluid thioglycollate medium, but omitting the 
agar and the resazurin sodium solution , sterilise as direc ted above. The pH after sterilisation is 7.1 ± 0.2. Heat 
in a water -bath prior to use and incubate at 30 -35 °C under anaerobic conditions.  
E.4 Soya -bean casein digest medium   
Pancreatic digest of casein                  17.0 g  
Papaic digest of soya -bean me al               3.0 g  
Sodium chloride                    5.0 g  
Dipotassium hydrogen phosphate                2.5 g  
Glucose monohydrate/anhydrous               2.5 g/2.3 g  
Water R                      1000 mL  
pH after sterilization  7.3 ± 0.2  
E.4.1 Dissolve the  solids in water R, warming slightly to effect solution. Cool the solution to  room 
temperature. Add 1 M sodium hydroxide, if necessary, so that after sterilisation  the solution will have a pH of 
7.3 ± 0.2.  
E.4.2 Filter, if necessary, to clarify , distribute  into suitable vessels and sterilise using a validated process. 
Store at a temperature  between 2 °C and 25 °C in a sterile well -closed container, unless it is intended  for 
immediate use. Do not use the medium for a longer storage period than  has been valid ated. Soya -bean 
casein digest medium is to be incubated at 20 -25 °C.  
The media used comply with the following tests, carried out before or in parallel with  the test on the product to 
be examined.  
E.5 Sterility  
Incubate portions of the media for 14 days. No growth of micro -organisms occurs.  DUS 1958 -1: 2018  
© UNBS 2018  – All rights reserved  13 
 Bibliography  
[1] British Pharmacopoeia, 201 7 
[2] ISO 11135 (both parts), Sterilization of health care products — Ethylene oxide  
[3] ISO 11137 (all parts), Sterilization of health care products — Radiation  
[4] ISO 17665  (all parts), Sterilization of health care products — Moist heat  
[5] US Pharmacopoeia 40, 2017  
 DUS 1958 -1: 201 8 
14 © UNBS 2018  – All rights reserved  
 Certification marking  
Products that conform to Uganda standards may be marked with Uganda National Bureau of Standards 
(UNBS) Certification Mark shown in the f igure below.  
The use of the UNBS Certification Mark is governed by the Standards Act, and the Regulations made 
thereunder. This mark can be used only by those licensed under the certification mark scheme operated by 
the Uganda National Bureau of Standards  and in conjunction with the relevant Uganda Standard. The 
presence of this mark on a product or in relation to a product is an assurance that the goods comply with the 
requirements of that standard under a system of supervision, control and testing in acc ordance with the 
certification mark scheme of the Uganda National Bureau of Standards. UNBS marked products are 
continually checked by UNBS for conformity to that standard.  
Further particulars of the terms and conditions of licensing may be obtained from the Director, Uganda 
National Bureau of Standards.  
DUS 1958 -1: 2018    
 
ICS 11.040.30  
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