Calibrated Inoculating Loops — Pro-Loops™

Q: What is the Evans Blue Dye calibration method (Cumitech 2A)?

The Evans Blue Dye method, defined in ASM's Cumitech 2A (Laboratory Diagnosis of Urinary Tract Infections), is the established calibration standard for quantitative urine culture inoculation loops — a loop is verified to consistently deliver the specified volume within acceptable tolerance using volumetric dye displacement. Pro-Lab's PL.120 and PL.125 certified loops are individually calibrated using this method and ship with a certificate of calibration.

Disposable Plastic Loops — PLD001 & PLD010

Sterile, single-use pink loops. 1,000 per pack. Proceeds donated to the Lynn Rae Memorial Cancer Research Fund.

PLD001

1 µl Disposable Plastic Loops

Single-use sterile pink loops for quantitative urine culture and oxidase-safe subculture. Highest sensitivity of all loop types in independent 484-sample study (PMID 38330685).

1,000 loops per pack
Oxidase-compatible (no false-positives)
Available: Fisher Scientific, Cardinal Health, VWR

$57.75 / 1,000 pack (~$0.058/loop)

Order PLD001 →

PLD010

10 µl Disposable Plastic Loops

Single-use sterile pink loops for standard 1/100 ml quantitative urine culture plating. Eliminates the false-positive oxidase interference of nichrome wire.

1,000 loops per pack
Oxidase-compatible (no false-positives)
Available: Fisher Scientific, Cardinal Health, VWR

$57.75 / 1,000 pack (~$0.058/loop)

Order PLD010 →

Why Clinical Microbiology Labs Choose Pro-Loops™

IQCP Documentation Arrives in Every Pack

Certified loops (PL.120, PL.125) ship with an individual calibration certificate traceable to the Evans Blue Dye Method per Cumitech 2A — designed to support IQCP documentation. Verify against your lab's current CAP Microbiology Checklist.

Cumitech 2A — ASM; pro-lab-direct.com PL.120/PL.125

Plastic Loops Outperform Metal for Urine Culture

In an independent 484-sample study, single-use 1 µl plastic loops showed the highest sensitivity of all loop types at both 10³ and 10⁴ CFU/ml diagnostic cutoffs — outperforming all metal loop types tested for sensitivity at both standard diagnostic cutoffs.

Ceylan et al., Diagn Microbiol Infect Dis 2024 — PMID 38330685

Six Calibrated Volumes — Every Quantitative Application

Pro-Loops™ offers nichrome wire loops in 1, 2, 2.5, 3.3, 5, and 10 µl — more calibrated nichrome volumes than the major generic distributors, which typically stock only 1 µl and 10 µl — covering every quantitative and semi-quantitative culture workflow from a single vendor.

pro-lab-direct.com — PL.100–PL.105 catalog

Eliminate Nichrome False-Positive Oxidase Errors

Disposable plastic loops (PLD001, PLD010) remove the most common source of false-positive oxidase reactions on the clinical bench — nichrome wire — replacing it with a sterile, single-use format backed by peer-reviewed performance evidence.

TestOxidase IFU — loop compatibility; PMID 38330685

Certified Calibrated Loops with IQCP Documentation — Every Pack Ships with a Cumitech 2A Certificate

CAP's IQCP requirements for quantitative culture workflows mean your calibrated loops need documented QC evidence on file. Pro-Lab's certified loops (PL.120, PL.125) ship with per-pack calibration certificates traceable to the Evans Blue Dye Method per Cumitech 2A — the certificate is designed to support your IQCP documentation — verify it meets your lab's current CAP Microbiology Checklist requirements.

Certified loops (PL.120/PL.125) include individual per-pack Cumitech 2A calibration certificates — IQCP-ready documentation on receipt
The calibrated loop method is the reference standard against which alternative urine culture methods are validated in peer-reviewed literature (Blondeau et al., J Clin Pathol 1995, PMID 7560194)
Single-use plastic loops (PLD001/PLD010) provide superior sensitivity for quantitative urine culture per independent 484-sample study (Ceylan et al. 2024, PMID 38330685)
All Pro-Loops™ manufactured under ISO 13485-certified quality system

Get a Quote — Certified Loops (PL.120/PL.125)

Stop Chasing Inconsistent Colony Counts — Calibrated Loops, Six Volumes, One Vendor

Inconsistent colony counts slow down the bench and frustrate clinicians — the most common cause is imprecise or deformed wire loops and the wrong volume for the specimen. Pro-Loops™ covers every quantitative and semi-quantitative application with six precisely calibrated volumes from a single manufacturer. For urine culture specifically, an independent 484-sample study found single-use 1 µl plastic loops outperformed all metal loop types for sensitivity at the critical diagnostic cutoffs your techs read every shift.

Six calibrated nichrome volumes: 1, 2, 2.5, 3.3, 5, 10 µl — widest range from a single manufacturer (PL.100–PL.105)
Plastic 1 µl loops: highest sensitivity (86.8% at 10³ CFU/ml; 75.9% at 10⁴ CFU/ml) of all loop types in 484-sample independent study (PMID 38330685)
Nichrome wire loops cause false-positive oxidase reactions — plastic or platinum loops required for oxidase testing (TestOxidase IFU)
Heavy gauge wire loops (PL.130–PL.133): same calibrated volumes, more durable construction, lower cost per pack ($81.68 vs. $102.22 for 25 loops)

Order Now — Disposable Plastic Loops

The Oxidase Problem Is the Loop Problem — Plastic Fixes It

Nichrome wire loops are the most common source of false-positive oxidase reactions on the clinical bench — you've repeated the test with a platinum loop and watched it go negative. Pro-Lab's PLD001 (1 µl) and PLD010 (10 µl) are sterile, single-use plastic loops that don't interfere with the oxidase reaction. They're available through Fisher Scientific, Cardinal Health, and VWR — and a peer-reviewed 484-sample study shows they're also more accurate than metal loops for quantitative urine culture.

Nichrome wire loops cause false-positive oxidase reactions — confirmed in oxidase reagent IFU (Pro-Lab TestOxidase IFU)
Plastic disposable loops eliminate oxidase false-positive interference — single-use, sterile, no metal
In 484 urine samples, plastic 1 µl loops showed highest sensitivity (86.8% at 10³ CFU/ml) vs. all metal loop types — using calibrated pipette as reference standard (PMID 38330685)
Available through Fisher Scientific, Cardinal Health, and VWR — order through your existing distributor account

Order PLD001 / PLD010 — 1,000 pcs

One Vendor for the Complete Inoculation Supply Chain — Loops, Holders, Sterilizer, Calibration Gauges

Most labs source their inoculation supply from three or four vendors — wire loops from one, holders from another, sterilizer from a third. Pro-Lab Direct stocks the complete inoculation workflow under one ISO 13485-certified manufacturer: calibrated wire loops in six volumes, heavy gauge loops, certified loops with IQCP documentation, sterile disposable plastic loops in 1,000-pack cases, insulated holders in two materials and two lengths, calibration gauges, and the Pro-Sterilizer™ bacti-cinerator. One PO. One free shipping threshold.

Full inoculation ecosystem: loops + holders + sterilizer + calibration gauges — single-vendor sourcing, ISO 13485 across all components
Free shipping on all orders — pro-lab-direct.com
Disposable plastic loops available through Fisher Scientific, Cardinal Health, and VWR (existing GPO/distributor contracts)
Cost per loop: $0.058 (PLD001/PLD010); $3.27/loop (heavy gauge, 25/pack); $4.09/loop (standard nichrome, 25/pack)

Get a Volume Quote

People Also Purchased

Frequently ordered alongside Pro-Loops™ — all from Pro-Lab Diagnostics, one PO.

TestOxidase™ Oxidase Reagent

PL.390

Perform oxidase testing with Pro-Loops™ plastic loops — nichrome loops cause false-positive reactions. Room-temp storage, 30-second read window.

View TestOxidase™ →

Microbank® PL.170C Cryopreservation System

Microbank® Preservation System

PL.170C-Series

Use Pro-Loops™ to pick colonies and inoculate Microbank® vials — cryopreservation bead system for long-term organism storage.

View Microbank® →

McFarland Turbidity Standards

PL.850-Series

Standardize bacterial inoculum density before susceptibility testing — used in the same quantitative culture workflow as calibrated loops.

View McFarland Standards →

PL.375

Kovacs' Reagent

PL.375 — 100 ml

Spot indole test reagent — use Pro-Loops™ plastic loops for swab method per IFU. Room-temperature storage, CLSI M35-A2 aligned.

View Kovacs' Reagent →

Complete Specs & Ordering

Wire Loop Specifications

Specification	Value	Source
Product line	Pro-Loops™ Inoculation Loops and Holders	pro-lab-direct.com
Manufacturer	Pro-Lab Diagnostics USA	pro-lab-direct.com
ISO certification	ISO 13485 (company-level)	pro-lab-direct.com footer
Loop material	Nichrome wire (standard/heavy gauge); 80/20 Ni/Cr wire (certified)	pro-lab-direct.com product pages
Available volumes — standard nichrome	1 µl (1/1000 ml), 2 µl (1/500 ml), 2.5 µl (1/400 ml), 3.3 µl (1/300 ml), 5 µl (1/200 ml), 10 µl (1/100 ml)	pro-lab-direct.com PL.100–PL.105
Loop diameters — nichrome	1 µl: 1.59 mm · 2 µl: 2.26 mm · 2.5 µl: 2.52 mm · 3.3 µl: 2.91 mm · 5 µl: 3.57 mm · 10 µl: 5.05 mm	pro-lab-direct.com product pages
Pack size — standard / heavy gauge	25 loops per pack	pro-lab-direct.com
Available volumes — heavy gauge	2.5 µl (1/400 ml), 5 µl (1/200 ml), 10 µl (1/100 ml)	pro-lab-direct.com PL.130–PL.133
Pack size — certified loops	5 loops per pack, protective case, calibration certificate	pro-lab-direct.com PL.120/PL.125
Calibration method — certified loops	Evans Blue Dye Method per Cumitech 2A (ASM)	pro-lab-direct.com PL.120/PL.125; Cumitech 2A
Certified loop material	80/20 Nickel-Chromium wire	pro-lab-direct.com PL.120/PL.125
Oxidase test compatibility — nichrome	NOT compatible — use plastic or platinum only (false-positive risk)	Pro-Lab TestOxidase IFU
Oxidase test compatibility — certified (80/20 Ni/Cr)	[GAP — confirm before publishing oxidase claims for certified loops]	Pending — see compliance flags
SDS	Not applicable — metal wire, non-hazardous material	Regulatory inference
FDA regulatory status	Class I exempt — laboratory consumable tool, not an IVD diagnostic device	Regulatory inference

Disposable Plastic Loop Specifications

Specification	Value	Source
SKUs	PLD001 (1 µl), PLD010 (10 µl)	pro-lab-direct.com
Volume	1 µl (PLD001); 10 µl (PLD010)	pro-lab-direct.com
Pack size	1,000 loops per pack	pro-lab-direct.com
Color	Pink	pro-lab-direct.com
Sterility	Sterile, single-use	pro-lab-direct.com
Oxidase compatibility	Compatible — plastic does not cause false-positive oxidase reactions	TestOxidase IFU; standard clinical microbiology practice
Published sensitivity — urine culture	1 µl: 86.8% at 10³ CFU/ml; 75.9% at 10⁴ CFU/ml — highest of all loop types tested (n=484)	Ceylan et al., Diagn Microbiol Infect Dis 2024;108(4):116192. PMID 38330685
List price	$57.75 per 1,000-pack	pro-lab-direct.com
Cost per loop	$0.058	Calculated from list price
Distributor availability	Fisher Scientific, Cardinal Health, VWR	pro-lab-direct.com product page notation
Charity program	Proceeds donated to Lynn Rae Memorial Cancer Research Fund	pro-lab-direct.com PLD001/PLD010

Price Reference — All SKUs

SKU	Product	Pack	List Price (USD)
PL.105	1 µl Nichrome Wire Loops	25	$102.22
PL.104	2 µl Nichrome Wire Loops	25	$102.22
PL.103	2.5 µl Nichrome Wire Loops	25	$102.22
PL.102	3.3 µl Nichrome Wire Loops	25	$102.22
PL.101	5 µl Nichrome Wire Loops	25	$102.22
PL.100	10 µl Nichrome Wire Loops	25	$102.22
PL.133	2.5 µl Heavy Gauge Wire Loops	25	$81.68
PL.131	5 µl Heavy Gauge Wire Loops	25	$81.68
PL.130	10 µl Heavy Gauge Wire Loops	25	$81.68
PL.125	1 µl Certified/Calibrated Wire Loops + Cumitech 2A Cert	5	$161.66
PL.120	10 µl Certified/Calibrated Wire Loops + Cumitech 2A Cert	5	$161.66
PLD001	1 µl Disposable Plastic Loops (Pink)	1,000	$57.75
PLD010	10 µl Disposable Plastic Loops (Pink)	1,000	$57.75
PL.106-6-1	Nickel Plated Brass Holder (6 in)	1	$41.83
PL.106-8-1	Nickel Plated Brass Holder (8 in)	1	$41.83
PL.107-6-1	Aluminum Holder (6 in)	1	$41.83
PL.107-8-1	Aluminum Holder (8 in)	1	$41.83
PL.B1000-01	Loop Holder Attachment (Pro-Sterilizer™)	1	$49.13
PL.121	Calibration Gauge for 10 µl Loops	1	$161.66
PL.126	Calibration Gauge for 1 µl Loops	1	$161.66

Frequently Asked Questions

Use a 10 µl calibrated loop (1/100 ml) for the standard ≥10⁵ CFU/ml bacteriuria threshold; use a 1 µl calibrated loop (1/1000 ml) for lower-threshold detection at ≥10³ CFU/ml — both per Cumitech 2A methodology. Both are available as certified loops (PL.120, PL.125) with individual calibration certificates. Source: Cumitech 2A — ASM; pro-lab-direct.com PL.120/PL.125

Yes — nichrome wire is known to produce false-positive results in the cytochrome oxidase test. Use platinum loops or single-use disposable plastic loops (PLD001, PLD010) for oxidase testing on isolated colonies to avoid this error. Source: Pro-Lab TestOxidase IFU — loop compatibility section

Yes — and independent research shows they outperform metal loops for urine culture sensitivity. A 484-sample study (Ceylan et al., Diagn Microbiol Infect Dis 2024; PMID 38330685) found single-use 1 µl plastic loops demonstrated the highest sensitivity of any loop type at both 10³ and 10⁴ CFU/ml thresholds, using calibrated pipette as the reference standard. Source: PMID 38330685

The Evans Blue Dye method, defined in ASM's Cumitech 2A (Laboratory Diagnosis of Urinary Tract Infections), is the established calibration standard for quantitative urine culture inoculation loops — a loop is verified to consistently deliver the specified volume within acceptable tolerance using volumetric dye displacement. Pro-Lab's PL.120 and PL.125 certified loops are individually calibrated using this method and ship with a certificate of calibration. Source: Cumitech 2A — ASM; pro-lab-direct.com PL.120/PL.125

CAP's IQCP requires documented QC evidence for tools used in quantitative culture workflows. Pro-Lab's certified loops (PL.120, PL.125) ship with individual calibration certificates traceable to Cumitech 2A — designed to support IQCP documentation. Verify against your lab's current CAP Microbiology Checklist. Source: CAP Microbiology Checklist 2024 — IQCP; Cumitech 2A; pro-lab-direct.com PL.120/PL.125

Standard nichrome loops (PL.100–PL.105) and heavy gauge loops (PL.130–PL.133) share the same calibrated volumes and loop diameters — heavy gauge uses thicker wire for added durability and resistance to deformation during repeated sterilization cycles, at a lower price per pack ($81.68 vs. $102.22 for 25 loops). Source: pro-lab-direct.com PL.100 and PL.130 product pages

Do not use nichrome or standard nickel-chromium wire loops for the oxidase test — these metals cause false-positive reactions. Use plastic (PLD001, PLD010) or platinum loops for oxidase testing. Wire loops are also not appropriate for applications requiring single-use sterility where cross-contamination between specimens is a concern — use sterile disposable plastic loops in those settings. Source: TestOxidase IFU — loop compatibility; standard clinical microbiology practice

Yes. The Pro-Sterilizer™ Bacti-cinerator (PL.B1000) sterilizes platinum and nichrome wire loops in 5–7 seconds at 815°C (1,500°F), eliminating live organisms without open flame. The Loop Holder Attachment (PL.B1000-01, $49.13) secures the loop holder for hands-free sterilization. Source: pro-lab-direct.com PL.B1000 product page

Product Information

“Pro-Loops™ inoculation loops are laboratory consumable tools for use in clinical microbiology specimen plating, organism subculture, and quantitative colony count workflows. They are not IVD diagnostic reagents and do not require FDA 510(k) clearance.”

Calibration statement (certified loops — PL.120, PL.125): Pro-Loops™ Certified/Calibrated Wire Loops are manufactured from 80/20 nickel-chromium wire and calibrated using the Evans Blue Dye Method per Cumitech 2A. Each pack of 5 loops is presented in a protective case and accompanied by the appropriate certificate of calibration. Source: pro-lab-direct.com PL.120/PL.125 product pages; Cumitech 2A — ASM

Quality system: All Pro-Loops™ products are manufactured under an ISO 13485-certified quality management system. Documentation available upon request for vendor qualification.

Hazard / SDS: Pro-Loops™ wire loops (nichrome wire, aluminum, nickel-plated brass) and plastic disposable loops are non-hazardous materials. No Safety Data Sheet (SDS) is required. Standard laboratory gloves recommended for specimen handling. Sterilized wire loops are hot immediately after incineration — allow to cool before contacting specimen.

Loop Compatibility and Limitations

Nichrome wire loops cause false-positive reactions in the cytochrome oxidase test. Use platinum loops or plastic disposable loops (PLD001, PLD010) for oxidase testing. [Source: TestOxidase IFU]
Wire loops must be sterilized between uses by incineration (815°C) or open flame; improperly sterilized loops can transfer organisms between specimens.
Calibrated loop volumes assume proper loop formation — deformed or bent loops will not deliver accurate volumes. Replace deformed loops immediately.
[GAP — pre-compliance flag]: The 80/20 Ni/Cr composition of certified loops (PL.120/PL.125) and their compatibility with the oxidase test has not been confirmed — do not make oxidase compatibility claims for certified loops until this is resolved.

Organisms and Use Cases

Quantitative Urine Culture (Primary Application)

Escherichia coli — most common uropathogen; 10 µl and 1 µl loops for CFU/ml quantitation
Klebsiella pneumoniae — gram-negative uropathogen; standard quantitative plating
Pseudomonas aeruginosa — oxidase-positive gram-negative rod (use plastic/platinum loop for oxidase test — not nichrome)
Enterococcus spp. — gram-positive uropathogen; blood agar and CNA quantitative plating
Staphylococcus saprophyticus — urease-positive gram-positive; quantitative culture threshold ≥10³ CFU/ml
Proteus mirabilis, Klebsiella oxytoca, Citrobacter spp. — common Enterobacterales uropathogens

Subculture and Isolation Workflows

Staphylococcus aureus / MRSA — subculture from selective media
Streptococcus spp. — streak plate isolation for beta-hemolysis observation
Campylobacter spp. — subculture from campy-selective media (1 µl loop preferred)
Neisseria gonorrhoeae — chocolate agar subculture; plastic or platinum loop recommended for oxidase confirmation

Culture Media Compatibility

Blood agar (BAP), CLED agar, MacConkey agar, Columbia CNA, Chocolate agar
All standard and selective media used in clinical microbiology

💗 Pink Loops Charity Program: PLD001 and PLD010 pink disposable loops — proceeds from every purchase are donated annually to the Lynn Rae Memorial Cancer Research Fund.

Pro-Loops™ Calibrated Inoculating Loops — Wire, Certified, and Disposable