Optimizing Sample Submission: From gDNA to FFPE and Cell Pellets

Submitting the right material, in the right way, is the simplest lever you have to prevent rework and delays in STR-based cell line authentication. This step-by-step tutorial translates lab reality into an audit-friendly, repeatable process — from choosing what to send (gDNA, cell pellets, or FFPE) to labeling, temperature control, metadata, and quick remediation when something goes off. Research use only (RUO).

Disclosure: CD Genomics is our product. Throughout this guide, we reference official thresholds from our STR service page and summarize packaging practices from our published submission guide.

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Document control — Version: v1.1 | Last reviewed: 2026-02-07 | Technical review: Dr. Yang H., Senior Scientist; QA review: [Name], QA Manager.

1. What you can submit — and why flexible inputs reduce friction

The fastest way to an interpretable STR profile is to match your available material to the most robust input type for capillary electrophoresis (CE) amplification. Flexibility reduces friction: you don't need to stop work if you don't have purified DNA on hand — cell pellets or FFPE can work, provided you set expectations and package correctly. These STR sample submission guidelines are written so a lab tech can follow them without guesswork.

1.1 The three most common inputs

Purified genomic DNA (gDNA) is the cleanest option and generally yields the most stable peak balance. Fresh or frozen cell pellets are a practical choice when your extraction pipeline is busy; they keep hands-on time low for submitters. FFPE blocks or sections are common in archival contexts; they are the hardest due to fragmentation and crosslinking but often workable with realistic expectations.

1.2 Common submission mistakes that delay projects

Ambiguous or duplicate sample IDs that don't match the manifest are the top cause of login delays. Quantity shortfalls — DNA submitted under threshold, or pellets with too few cells — are next. Temperature mismatches in transit create thaw–refreeze cycles that hurt STR amplification, especially for pellets. Leaky primary tubes or unsealed caps without secondary containment lead to carrier incidents and rejections. And missing context (no passage number, no expected reference cell line name, unclear comparison request) forces back‑and‑forth emails that can easily cost you two to three days.

1.3 What this guide provides

You'll find explicit minimums and recommended ranges for each input type; stepwise packaging and shipping SOPs that can be handed to a lab technician; and a metadata checklist that maps cleanly to typical LIMS fields. Follow these STR sample submission guidelines end‑to‑end and your first‑pass success rate should rise significantly.

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2. Recommended inputs and handling by sample type

This section lists acceptance thresholds drawn from the CD Genomics STR service page and operational handling assembled from our submission guidelines and standard lab practice. Numbers are explicit where our page publishes them; where a value is not published (e.g., FFPE section thickness), we flag a consult‑required step rather than invent a number.

Consensus snapshot — how external standards align with these STR sample submission guidelines Across the field, consensus standards and major cell banks reinforce the practical thresholds used here: ASN‑0002 (ANSI/ATCC) and ATCC submission guidance recommend using multiple core STR loci (typically ≥8 autosomal loci plus amelogenin, with broader panels up to 13+ loci) and apply an ~80% allele‑match rule for confirming identity. In practice, institutional cores publish similar pragmatic minima for gDNA and spotted cell material; where local protocols differ, follow the conservative, consult‑first approach flagged in this guide.

Key third‑party references (select excerpts)

According to the ANSI/ATCC consensus, ANSI/ATCC ASN‑0002: Authentication of Human Cell Lines, STR interpretation should use a standard core panel and an algorithmic percent‑match framework; ASN‑0002 supports an approximate 80% match threshold for confirming human cell‑line identity, which we adopt here as the practical rule‑of‑thumb.

• ASN‑0002 standard: recommends standardized STR panels and an interpretation framework using percent‑match calculations (see ANSI/ATCC ASN‑0002: Authentication of Human Cell Lines for method and match thresholds).
• ATCC cell authentication instructions: practical submission procedures (e.g., FTA card spotting and recommended suspension densities) and sample handling notes are summarized in ATCC Human Cell STR Testing — submission instructions.
• ICLAC guidance: operational best practices and frequentist interpretation context for STR results are summarized in the ICLAC Guide to Human Cell Line Authentication.

2.1 Purified gDNA: ranges, storage, and shipping

Send at ≥50 ng/µL and ≥20 µL total volume (measured with a fluorometric assay such as Qubit). Source: official thresholds on the CD Genomics STR service page: Cell line identification and authentication via STR. Use DNase‑free water, elution buffer, or 10 mM Tris pH ~8.0 in low‑bind tubes. Ship with a cold pack to keep the sample cool and avoid repeated freeze–thaw cycles. See our \[Sample Submission Guidelines (PDF)\](/pdf/main/sample-submission-guidelines.pdf) for packaging details. Avoid phenol carryover and residual ethanol; if you used magnetic bead cleanup, verify beads are not visible. With optimized workflows, authentication from ~1 ng total DNA may be possible, but low input increases the risk of partial profiles due to allelic dropout; set expectations accordingly (see manufacturer guidance cited in References).

How your submission becomes an STR report (what the allele table means).
For locus‑by‑locus match logic and typical acceptance thresholds (e.g., ≥80% match), review our service page overview: STR report interpretation and workflow.

Practical micro‑example (neutral): When we receive gDNA at ≥50 ng/µL with clean absorbance ratios and stable fragment integrity, the resulting electropherograms typically show balanced peak heights across core loci, making match scoring straightforward under the ≥80% criterion described on the service page.

2.2 Fresh/frozen cell pellets: counts, wash, and label hygiene

Target ≥5×10^5 cells; acceptable submission volumes range from 18 µL to 2 mL for suspensions. Ship on a cold pack. Source: Cell line identification and authentication via STR. A rinse in 1× PBS before freezing can remove inhibitors present in culture media, improving downstream amplification.

Submitter‑side SOP example you can copy:

1. Harvest the culture; pellet at 300–500 × g for 5 minutes, remove supernatant.

2. Add 1 mL 1× PBS, flick to resuspend, pellet again (500 × g, 5 minutes); remove supernatant completely.

3. If shipping as a pellet, cap and Parafilm‑seal. If shipping as a suspension, ensure the volume is between 18 µL and 2 mL.

4. Label both the tube side and cap with the exact Sample ID; apply a barcode sticker if available. Place tubes for different lines in separate racks to prevent swap‑ins.

5. Keep cold on gel ice packs; avoid thaw–refreeze events.

Receipt‑side QC you should expect: visual inspection for leaks, login of barcodes/IDs, fluorometric DNA quant after extraction, and a quick integrity check when appropriate. If the pellet mass is visibly small or if extraction yields are low, we'll confer with you on a remedial plan the same day.

2.3 FFPE tissue: consult for sections; set realistic outcomes

FFPE is the hardest input because formalin fixation and block aging create crosslinks and fragmentation that can lead to partial profiles. Before shipping, contact us for section thickness/quantity guidance specific to your block; our STR service page does not publish numeric section specs, so we prefer to confirm details case‑by‑case. Use Ordering or Contact us to coordinate. If you plan to ship deparaffinized sections or extracted DNA from FFPE, package it as you would gDNA and use a cold pack. If shipping intact FFPE sections, protect from heat extremes and crush risk; ambient to cool is typical. Older blocks or prolonged fixation increase allelic dropout. Short‑amplicon (miniSTR) designs can improve locus recovery, but complete profiles are not guaranteed. Think of FFPE like a library whose pages are brittle: you can still read many chapters, but torn pages mean some loci won't be legible on the first pass.

FFPE consult checklist (what to include in your message): block age (year), fixation duration (hours), fixative used (10% NBF typical), whether sections will be deparaffinized before shipping, and whether a prior extraction was attempted. This lets our team suggest the most appropriate extraction approach and set turnaround expectations.

2.4 Low‑input or challenging samples: outcome ranges

Below‑threshold gDNA or sparse pellets may still yield partial profiles. Provide all context you have (input amount, extraction method, age of material) so our team can select amplification conditions appropriately. For highly degraded DNA, locus‑dependent dropout is expected; if an initial run is partial, we'll coordinate a remediation path (e.g., re‑extraction, additional aliquots, or alternate primer sets where applicable) within RUO practice. As kit documentation notes, many modern STR kits produce complete profiles near 0.5–1 ng DNA and partial profiles at lower inputs; these ranges help explain why consistency improves when you meet or exceed the thresholds in these STR sample submission guidelines.

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3. Metadata checklist (prevents back‑and‑forth)

You can copy this block into your LIMS template so a lab tech can assemble a complete submission in one pass. Unique IDs and explicit comparison instructions are the two biggest time savers.

3.1 Sample ID conventions

Assign a unique Sample ID with no re‑use across projects; use a scannable barcode where possible. Mirror the exact ID on the tube side and the cap (black permanent ink; avoid solvents that smear on cold packs). In the manifest, map each Sample ID to the project name/ID, submitter, and ship date.

3.2 Passage/source/reference name (context that speeds interpretation)

Record passage number and a brief culture timeline for the aliquot being submitted. Add the intended reference cell line name and supplier/catalog if known, the expected species, and any growth conditions that may introduce inhibitors (e.g., high serum lots). This context reduces back‑and‑forth and accelerates reporting.

3.3 Define comparisons upfront

Choose one: a single‑sample identity check against a prior profile; a cross‑sample panel (e.g., batch of clones); or a database match against DSMZ/ATCC/JCRB. If you have a prior STR result, include the report ID/date and which loci were genotyped.

If database matching is your priority, here's how DSMZ/ATCC/JCRB comparisons work.

Mini table you can paste into your manifest:

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4. Packaging and shipping — STR sample submission guidelines you can hand to a tech

This section is written so you can hand it to a technician and expect consistent execution.

4.1 Tube types, sealing, and secondary containment

Use 1.5 mL low‑bind microcentrifuge tubes for gDNA and small pellets; cryovials for larger pellets or frozen stock. Tighten caps and wrap with Parafilm to prevent leaks. Place the labeled primary tube into a 50 mL conical or a sealable biohazard bag with absorbent material; cushion to prevent crushing. The ID on the tube must match the submission form exactly; label both side and cap, and apply a barcode label if available.

4.2 Temperature decision matrix

The aim is to preserve integrity and avoid thaw cycles. Think of temperature control as guardrails: stay inside the lane and you avoid jarring transitions that damage DNA.

4.3 Chain‑of‑custody (CoC) and documentation for B2B programs

Prepare a manifest mapping Sample IDs to barcodes, submitter, date/time of handoff, and the receiving party. Keep a signed CoC that accompanies the package; retain a scanned copy in your LIMS. Email the submission form and carrier tracking to your project contact before the shipment leaves your facility. For general process steps and forms, see Ordering, our Sample Submission Guidelines (PDF), and FAQs.

Receipt QC at the lab (what we do on arrival): we confirm physical integrity and labeling, register IDs and barcodes, perform fluorometric quantification after extraction (pellets/FFPE) or on arrival (gDNA), and may check fragment distribution for degraded inputs. If anything is off, we provide a same‑day status with options.

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5. When something is off (fix it fast)

Things happen. Here's how to recognize common issues quickly and what to provide so remediation can start the same day.

5.1 Too little DNA or inhibitors

Low overall peak heights, locus‑dependent dropout, or inconsistent amplification across replicates usually point to insufficient template or inhibitors. Concentrate gDNA and verify with Qubit; ensure residual ethanol is fully removed. For pellets, consider a repeat extraction with a silica cleanup and share the extraction method used. For FFPE or visibly degraded DNA, set expectations for partial profiles and discuss short‑amplicon strategies. In your message, include the extraction and quant methods, cleanups performed, the age of material, and the shipping temperature used.

5.2 Mixed labeling risk indicators

More than two alleles at many autosomal loci or a discordant species call often signals a mix‑up. Audit barcodes and labels against the manifest; check bench records for concurrent lines; pause work on the batch until IDs are confirmed. If necessary, re‑culture from the master stock and resubmit with reinforced labeling SOPs.

5.3 Suspected contamination or drift — context to provide

Provide a quick timeline of culture passages, any co‑culture or shared incubator history, and prior STR results if available. Indicate whether you want a cross‑sample panel (compare multiple samples) or a database check.

Cross‑contamination and drift troubleshooting for cell culture programs.

For pricing/turnaround/onboarding steps, see the STR service workflow overview.

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Closing and next steps

Ready to submit? You can review the ordering steps and typical timelines on our Ordering page or submit a request directly via Order Online. If you're shipping FFPE, a brief pre‑submission note with block age and fixation time helps us tailor extraction and set expectations. Follow these STR sample submission guidelines and you'll dramatically cut down on emails, repeats, and lost time.

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Related Services

• Cell line identification and authentication
• Microsatellite genotyping service
• Multiplex PCR sequencing
• Sanger sequencing
• Amplicon sequencing services
• Genomic data analysis

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Author

Yang H. — Senior Scientist, CD Genomics; University of Florida.

Yang is a genomics researcher with over 10 years of research experience in genetics, molecular and cellular biology, sequencing workflows, and bioinformatic analysis. Skilled in both laboratory techniques and data interpretation, Yang supports RUO study design and NGS-based projects.

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References:

1. ATCC. Human Cell STR Testing — Sample Submission Instructions. PDF: https://www.atcc.org/-/media/product-assets/documents/catalog-services/str_sample-human-submission-instructions.pdf
2. ATCC. STR Authentication: Using the ATCC Public STR Database (tutorial). https://www.atcc.org/-/media/resources/instruction-guides/atcc_str_database_tutorial.pdf
3. ANSI/ATCC. Human Cell Line Authentication: Standardization of STR Profiling (ASN‑0002). Landing page: https://www.atcc.org/products/135-ansi-str
4. Chen, H. et al. (2014). STR profiling success from FFPE tissues: impact of fixation time and block age. Forensic Science International: Genetics, 12, 80–87. https://doi.org/10.1016/j.fsigen.2014.05.009
5. Masters, J. R. (2002). HeLa cells 50 years on: the good, the bad and the ugly. Nature Reviews Cancer, 2(4), 315–319. https://doi.org/10.1038/nrc775