McFarland Standards — Latex-Based, CLSI-Aligned Inoculum Reference
Pro-Lab McFarland Standards are lot-tested to CLSI M02 %T acceptance ranges and ship without hazmat surcharges — so your AST workflow never waits on a supplier quote.
Testimonials coming soon — request from top 3 accounts.
Store at 15–30°C — No Cold Chain
Pro-Lab McFarland Standards are stable at room temperature for up to 2 years — no cold pack receiving, no waiting for a refrigerated tube to equilibrate before use.
IFU Rev 2022 08
Lot-Tested QC Ranges — CAP/CLIA Ready
Every lot is manufactured and released against tight %T acceptance ranges per CLSI M02 (0.5 standard: 78.5–84 %T). Certificate of Analysis available on request.
IFU Rev 2022 08
GHS Not Classified — No Hazmat Surcharge
Pro-Lab's polystyrene latex formulation carries no GHS signal word, no pictograms, and no H-statements. No sodium azide means no special drain-disposal restrictions.
SDS Rev 3, May 2020
Order Direct — No Rep, No Quote Required
Order online in 2 minutes. Complete set (PL2350, 0.5–4.0) or individual standards by concentration — published prices, instant checkout, ships from stock.
pro-lab-direct.com
Designed for Every Lab Role
Your CLSI-Aligned Inoculum Standard. In Stock. No Quote Required.
Every clinical microbiology lab performing disk diffusion AST needs a reliable 0.5 McFarland Standard. Pro-Lab's latex-based formulation stores at room temperature, ships non-hazardous, and is available direct — no distributor account, no request-a-quote delay. Order the complete set (PL2350, 0.5–4.0) or individual standards by concentration; each lot ships with documented %T acceptance ranges per CLSI M02.
- check Lot-tested to CLSI M02 %T acceptance ranges — QC documentation ready for CAP/CLIA survey
- check Room temperature storage (15–30°C) — no cold chain receiving complications
- check No sodium azide — standard waste disposal, no drain-disposal restriction
Q: We have a Fisher/VWR contract — can we still order?
Yes. McFarland Standards typically fall below the contract-routing threshold ($500 or under at most institutions) — no contract change required. Also available through VWR (cat. # 21762007).
CLSI-Compliant Turbidity Standards. Direct Vendor. Simple Procurement.
Lab directors need two things from a McFarland Standard supplier: defensible QC documentation for accreditation, and reliable availability when the primary distributor goes on backorder. Pro-Lab Direct ships from stock, publishes lot-specific %T acceptance ranges aligned with CLSI M02, and provides SDS and IFU documentation for your regulatory file on demand.
- check CLSI M02-aligned QC documentation — %T acceptance ranges per lot for accreditation file
- check Non-hazardous formulation — no GHS pictograms, no H-statements, no hazmat shipping costs
- check Priced $4.55 below Remel complete set — $390.76 vs. R20421 $395.31
Q: How does Pro-Lab's documentation satisfy CAP/CLIA requirements?
Each lot ships with documented %T acceptance ranges per CLSI M02. IFU and SDS are available for download at any time. Certificate of Analysis available on request for any lot number.
Visual Comparison or Densitometer — Both Methods Covered.
The bench tech using McFarland Standards every shift needs the same thing every time: a clear turbidity endpoint, a tube that hasn't expired, and no surprises. Pro-Lab's latex formulation gives you a consistent suspension — gently invert before use, compare against the density card, done. Two-year shelf life means less mid-shift expiry scrambling.
- check Density card included — black/white bar visual comparison; no instrument required
- check Densitometer compatible — calibration procedure included in IFU
- check 2-year shelf life — less expiry waste, less mid-shift stockout
Q: Can I use this with my densitometer?
Yes. Confirm your densitometer tube format matches the McFarland Standard tube — if different, decant into your routine-use tube before calibration. Clean tube exterior before each reading.
Complete Set & Individual Standards
Order the complete set or individual concentrations. The 0.5 standard is the required inoculum reference for all CLSI M02 and EUCAST disk diffusion protocols.
McFarland Standard Set
0.5, 1.0, 2.0, 3.0, 4.0 — protective carrying case + density card included
$390.76
McFarland Standard 0.5
Required for all CLSI M02 & EUCAST disk diffusion inoculum preparation
$98.13
Individual Standards 1.0–4.0
Used for identification kits and MIC protocols. Each sold separately.
$98.13 each
Complete Your AST Workflow
Products frequently purchased alongside McFarland Standards
TestOxidase — PL.390
Rapid cytochrome oxidase test — used post-culture to identify oxidase-positive gram-negative organisms before susceptibility testing.
Pro-Loops — 1 µL Disposable Loops PLD001
Disposable plastic loops for bacterial suspension preparation — no flaming, no nichrome contamination risk.
Pro-Loops — 10 µL Disposable Loops PLD010
10 µL loops for higher-volume suspension preparation and inoculation steps in susceptibility testing workflows.
People Also Purchased
Frequently ordered alongside McFarland Standards in clinical microbiology and susceptibility testing workflows.
PL.170C-Series
Microbank® Microbial Preservation System
Store QC organisms used for McFarland calibration — calibrate suspension to 3–4 McFarland before Microbank® inoculation.
View Microbank® →
PLD001 / PLD010
Pro-Loops™ Calibrated Inoculation Loops
Sterile calibrated loops for inoculation after McFarland suspension preparation — same lab workflow, same vendor.
View Pro-Loops™ →
PL.390
TestOxidase™ Cytochrome Oxidase Reagent
Identify organisms before preparing McFarland suspensions for susceptibility testing — part of the same bacterial ID workflow.
View TestOxidase™ →
PL.030
Prolex™ Streptococcal Grouping Kit
Latex Lancefield grouping for Strep identification — confirm organism identity before McFarland suspension and susceptibility testing.
View Strep Kit →Technical Specifications
All values sourced from IFU Rev 2022 08 and SDS Rev 3, May 2020.
| Complete set SKU | PL2350 |
|---|---|
| Individual SKUs | PL.2300 (0.5 · $98.13) · PL.2301 (1.0 · $98.13) · PL.2302 (2.0 · $98.13) · PL.2303 (3.0 · $98.13) · PL.2304 (4.0 · $98.13) |
| Formulation | Polystyrene latex particles in buffer solution |
| Storage temperature | 15°C–30°C (room temperature) — do not freeze |
| Shelf life | Up to 2 years from manufacture date |
| GHS signal word | None — GHS Not Classified · No pictograms · No H-statements |
| Sodium azide | None · Standard lab waste disposal · No drain-disposal restriction |
| Hazmat shipping | Not required — not regulated under DOT, IATA, or IMDG |
| Density card included | Yes — black/white bars for visual turbidity comparison |
| Densitometer compatible | Yes — calibration procedure included in IFU |
| Regulatory alignment | CLSI M02 (M02-A10 cited in IFU) · CLSI M100 · EUCAST Disk Diffusion Method |
| IFU / SDS revision | IFU Rev 2022 08 · SDS Rev 3, May 2020 |
QC %T Acceptance Ranges — Lot Testing
Per CLSI M02. Certificate of Analysis available on request for any lot number. Download IFU Rev 2022 08 →
| Standard | %T Low | %T High | Approx. Cell Density |
|---|---|---|---|
| 0.5 | 78.5 | 84 | 1.5 × 10⁸ cells/mL |
| 1.0 | 54 | 61 | 3.0 × 10⁸ cells/mL |
| 2.0 | 35 | 42 | 6.0 × 10⁸ cells/mL |
| 3.0 | 22 | 28 | 9.0 × 10⁸ cells/mL |
| 4.0 | 14 | 20 | 12.0 × 10⁸ cells/mL |
How to Use McFarland Standards
Visual Comparison Method
- 1Invert McFarland Standard tube gently several times to uniformly suspend latex particles
- 2Prepare bacterial suspension from log-phase growth in sterile saline or equivalent medium
- 3Hold both tubes against the black-and-white bars on the enclosed density card
- 4Equal disappearance or distortion of the black bar confirms matched turbidity
SOURCE: IFU Rev 2022 08, Procedure section
Densitometer Method
- 1Confirm densitometer tube format matches McFarland Standard tube; decant into routine-use tube if different
- 2Invert McFarland Standard tube gently; clean tube exterior (fingerprints affect readings)
- 3Calibrate densitometer using McFarland Standards
- 4Adjust bacterial suspension turbidity to target McFarland value using calibrated densitometer
SOURCE: IFU Rev 2022 08, Densitometer Procedure
Limitations (from IFU)
- • Colored media: Visual comparison method cannot be used — incorrect results will occur. Use densitometer method.
- • Old cultures: Stationary-phase cultures do not produce expected cell counts. Use log-phase growth only.
- • Instrumentation: Only spectrophotometer/densitometer-calibrated comparisons are validated. Do not improvise.
SOURCE: IFU Rev 2022 08, Limitations section
Pro-Lab vs. Remel — Side-by-Side
Prices confirmed on pro-lab-direct.com and fishersci.com. Note: Remel SDS/IFU not yet retrieved — cells marked "Not confirmed" should be verified before publishing competitive advertising.
| Feature | Pro-Lab (PL2350) | Remel (R20421) |
|---|---|---|
| Price — Complete Set | $390.76 | $395.31 |
| Individual pricing | Published online | Quote-only on Fisher |
| Purchase method | Direct online — no account needed | Fisher account required |
| Sodium azide | None (SDS confirmed) | Not confirmed — verify Remel SDS |
| GHS classification | Not Classified (non-hazardous) | Not confirmed |
| Range | 0.5–4.0 (5 standards) | 0.5–4.0 (5 standards) |
| Density card | Yes | Yes (plastic case) |
Prices confirmed 2026-04-06 · battlecard-remel.md · SOURCE: pro-lab-direct.com; fishersci.com
Frequently Asked Questions
McFarland Standards are latex-based turbidity reference standards used in clinical microbiology labs to calibrate bacterial inoculum density before performing antimicrobial susceptibility testing (AST). The 0.5 McFarland Standard is required by CLSI M02 and EUCAST disk diffusion protocols for inoculum preparation. Pro-Lab's latex formulation stores at room temperature (15–30°C) with a 2-year shelf life — no cold chain required. SOURCE: IFU Rev 2022 08; CLSI M02; EUCAST
No. Pro-Lab McFarland Standards store at 15–30°C (room temperature). Do not freeze. Room-temperature stability eliminates cold-chain receiving and cold storage requirements. SOURCE: IFU Rev 2022 08
Up to 2 years from the date of manufacture. The expiry date is printed on the tube label — discard after the printed date. The 2-year shelf life reduces expiry waste vs. products with shorter stability. SOURCE: IFU Rev 2022 08
No. Pro-Lab's formulation contains polystyrene latex particles in a buffer solution — no sodium azide. Standard laboratory waste disposal applies with no drain-disposal restrictions. SOURCE: SDS Rev 3, May 2020, Section 3
Yes. Each lot is manufactured and released against %T acceptance ranges aligned with CLSI M02 (IFU references CLSI M02-A10). Ranges: 0.5: 78.5–84 %T · 1.0: 54–61 %T · 2.0: 35–42 %T · 3.0: 22–28 %T · 4.0: 14–20 %T. See QC table above. SOURCE: IFU Rev 2022 08
Yes. All Pro-Lab McFarland Standard sets include a density card with black and white bars for visual turbidity comparison. A densitometer is not required when using the visual comparison method — compare the bacterial suspension against the card until the black bar shows equal disappearance. SOURCE: IFU Rev 2022 08
Yes. The IFU includes a densitometer calibration procedure. Confirm the routine-use tube format matches the McFarland Standard tube; if different, decant the standard into the routine-use tube before calibration. Clean tube exteriors before each reading — fingerprints and debris affect the result. SOURCE: IFU Rev 2022 08
Do not use visual comparison with colored or turbid media — the IFU states this will not provide proper contrast and incorrect results will occur. Use the densitometer method in those cases. Also: use log-phase cultures only. Stationary-phase cultures do not produce expected cell counts even with a correct turbidity match. SOURCE: IFU Rev 2022 08, Limitations
Product Documentation & Regulatory Information
Intended Use
"The McFarland Standards are for use as part of a quality control program for adjusting densities of bacterial suspensions that are used for identification and susceptibility testing."
SOURCE: IFU Rev 2022 08, Intended Use section
Safety Data Sheet
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Complete Set $390.76 (PL2350) — ships non-hazardous, no surcharge
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Download IFU
Rev 2022 08 — QC acceptance ranges, procedure, lot testing documentation
Download IFU (PDF)